Disclosed are stable portable oral care confectionery compositions which provide enhanced oral malodour benefits combined with enhanced anti-calculus benefits, wherein the confectionery compositions comprise:

The present invention relates to confectionery compositions that comprise polyphosphate with an average anion chain length of greater than or equal to 3; a metal cation wherein the ratio of polyphosphate to metal cation is in the range of from about 10:1 to about 1:1 and wherein the confectionery composition comprises less than 10%, by weight of the composition, water. Preferably this invention relates to non-cariogenic or so called xe2x80x9csugar freexe2x80x9d chewing gum confectionery compositions. More particularly this invention relates to compositions that treat or prevent oral malodour, treat or prevent calculus and have surface conditioning effects in the oral cavity of a subject. Compositions of the present invention are suitable for use by humans or animals.
Oral malodour or halitosis, which is commonly referred to as bad breath, is the result of volatile sulphur compounds, carboxylic acids and amines building up in the oral cavity. The malodourous compounds are generated primarily through putrefactive action of oral microorganisms on sulphur containing amino acids, peptones or proteins found in the mouth. Such micro-organisms are readily available in saliva and dental plaque and may be derived from proteinaceous food particles trapped between the teeth, in the gingival crevice or adhering to the mucous membranes and the irregular surface of the tongue as well as exfoliated oral epitheleum, food debris and the like. In addition oral malodour may be the result of poor oral hygiene, digestive system problems, disease, diet or a combination of any of these factors. Not only is oral malodour unpleasant but its presence can be indicative of poor oral hygiene and can also be one of the first signs of some more severe underlying problems. This is because the build up of putrid matter which causes malodour can also lead to the formation of plaque, the origin of dental caries, gingivitis and dental calculus. Regular brushing of teeth can help to minimise oral malodour. However, even regular brushing is not sufficient to remove all of the food and oral bacteria deposits that adhere to the oral surfaces and, in severe cases it is unable to eliminate oral malodour.
To date oral malodour products have been formulated to comprise a wide range of materials that kill the oral bacteria contributing to the oral malodour. Such materials include agents such as triclosan, chlorhexidine, quaternary ammonium salts and camphorated parachlorophenol. However, these materials can be harsh, and can only be dosed in limited daily amounts and as such are not necessarily suitable for use in a product to be used several times a day. In some cases they may also cause undesirable side effects such as staining, altered taste etc.
More recently trends have been directed towards the use so called natural materials, especially extracts, to provide a wide range of benefits in personal care products. Herbal extracts of gold thread and honeysuckle have been reported (JP 57-85319/U.S. Pat. No. 5,741,138); herbal curry plant extract has been disclosed in JP 10-182,388 for combating halitosis; cranberry extract has been disclosed in WO 96/28135 for is antimicrobial and antibacterial properties; and DE 4,221,103 discloses compositions comprising a wide range of herbal extracts for oral hygiene. Polyphenols have been identified as an important active in a wide range of herbal extracts. Examples of oral care disclosures include WO 01/17494 which discloses dentifrice compositions comprising tea polyphenols; US/PCT/00/11258 which discloses dentifrice compositions comprising polyphenol herbal extracts; and EP 1,013,261 which discloses a spray liquid comprising polyphenol for the masking of halitosis. Whilst the teachings of the prior art are directed towards compositions with limited deodorising or anti-bacterial effects the products themselves have limited activity and are unstable leading to unattractive discolouration over time and further reduction in efficacy. There remains a need for a stable oral care product that is able to deliver effective malodour control benefits.
Metal cations have also been considered for inclusion in oral compositions for treating oral malodour. Disclosures include U.S. Pat. No. 5,833,952 which discloses compositions comprising tin salts, optionally in combination with zinc salts; WO 99/17735 which discloses a metal ion amino acid chelate; U.S. Pat. No. 6,123,925 which discloses a dentifrice comprising ceramic particles in combination with anti-microbial metal ions. However there remain several problems in preparing compositions comprising metal ions for combating oral malodour. These include that the presence of high level of metal cation can often destabilise other elements of the composition, the metal ions become easily chelated to other products and are therefore not efficacious, tightly controlled regulatory limits and the products tend to be highly astringent thus having unacceptable taste profiles. Despite these disadvantages the use of metal cations for combating oral malodour has several benefits. These include that the materials are very cheap, the materials are easy to work with and the metal cations have good recorded efficacy. Thus there remains a desire to continue to work with metal cations to develop a stable, pleasant oral care product able to deliver effective and long lasting malodour benefits.
Oral malodour is closely linked with the build up of plaque. Dental plaque is the name given to a deposit of material that accumulates on the teeth and adjacent surfaces of the oral cavity. It is the product of microbial growth in the oral cavity, primarily derived from the food/sugar residues in the mouth. Mucoproteins, minerals and food deposits present in the saliva, and dead cells in the mouth, also contribute to the formation of plaque. The build up of plaque enhances the formation of calculus, a hard mineral material that deposits on teeth. Calculus is formed when calcium phosphate crystals, which become entangled in the plaque film, become sufficiently closely packed together to aggregate and become resistant to deformation. The build up of both plaque and calculus on the teeth leads to a general decline in oral health resulting in an increase in the rate of formation of dental caries, an increase in the prevalence of gum disease and can also contribute to the staining of teeth and the presence of malodour. If left untreated these conditions can lead to severe oral disease and deterioration of the gums and teeth.
Several anti-plaque and anti-calculus agents are known in the art. One such material is linear or cyclic dehydrated polyphosphate, which is known to be an effective calcium/magnesium ion suppressor, a sequestrant and/or chelating agent and an effective inhibitor of calculus formation. Well-known examples are the water soluble hexametaphosphates, tripolyphosphate and pyrophosphates and the like. These materials have been widely disclosed in oral care compositions such as dentifrice. Examples of such disclosures include U.S. Pat. No. 5,094,844 which discloses oral compositions comprising tripolyphosphate; U.S. Pat. No. 4,460,565 which discloses oral compositions comprising two or more fluoride compounds and an agent capable of supplying calcium ions to the teeth optionally in conjunction with a cyclic phosphate; WO 99/12517 which discloses oral compositions comprising tripolyphopshate, pyrophosphate and PVP; JP 10-182388 which discloses compositions comprising cyclic and linear condensed phosphoric acid and curry extract and JP 9-295942 which discloses an agent for preventing tooth decay comprising at least 1 meta phosphate. Such polyphosphates are also known to provide a buffering effect within oral compositions comprising zinc (U.S. Pat. Nos. 4,170,632 and 4,170,633 both to Wagenknecht). In addition, the pending patent application PCT/US00/30808 reports that long chain linear polyphosphates with an average anion chain length of greater than or equal to 4 provide novel surface conditioning benefits to the teeth and mucosa. This leads to an improved cleaning impression. However, one of the commonly known issues with polyphosphates, especially long chain polyphosphates, is that they are rapidly hydrolysed and therefore their efficacy is reduced over time. Furthermore, when the polyphosphate is introduced into the oral cavity, salivary enzymes quickly hydrolyse the material, again leading to a reduction in desired efficacy. As such there are several opportunities to further optimise the formulation of oral care products comprising polyphosphate to overcome these hydrolysis issues.
Given the close links between the formation of oral malodour and dental plaque it would be ideal to develop an oral care product which had both superior benefits in combating oral malodour and also superior anti-plaque benefits. To date little industry effort has specifically been directed to this purpose although JP 10-182388 does disclose compositions comprising cyclic and linear condensed phosphate acid and curry extract wherein the curry extract has halitosis benefits.
Given the known benefits of metal cations for combating oral malodour it would be ideal to develop an oral composition that comprises a combination of polyphosphate and metal cations for treating and preventing both oral malodour and dental plaque. To date few attempts have been successfully made to combine metal cations with polyphosphates in a single phase oral care composition. The disclosures in the art include U.S. Pat. No. 5,833,952 which discloses a composition comprising a tin salt, preferably tin pyrophosphate optionally in combination with a zinc salt; WO 99/17735 which discloses a metal ion amino acid chelate optionally in combination with pyrophosphate; U.S. Pat. No. 5,094,842 which discloses compositions comprising vitamin C, copper salt where the preferred tin salt is tin pyrophosphate; U.S. Pat. No. 5,188,820 which discloses oral compositions comprising a mixture of tin and zinc salts wherein the preferred tin salt is tin pyrophosphate; pending patent application PCT/US00/17177 which discloses chewing gum compositions comprising long chain polyphosphate and zinc lactate; and EP 528,458 which discloses compositions comprising phosphopeptide, soluble polyphosphate, and zinc salt and optionally comprising tin salts. Whilst the disclosures of the prior art teaches the combination of metal ions with pyrophosphate and short chain polyphosphates their remains a need for a composition which demonstrates both effective anti-plaque efficacy and effective oral malodour efficacy. Furthermore there remains a need to formulate an effective oral malodour composition, which has acceptable astringency levels.
Furthermore, there is currently a movement in the oral care industry to develop portable oral care product forms which can be used several times a day, particularly after eating. It is hoped that such a product will improve the oral hygiene of consumers. In addition, such a product would make it easier to provide good oral hygiene to children and pets where it is not always easy or possible to regularly brush the teeth.
Confectionery compositions which are popular with both children and adults alike and which are retained in the oral cavity for substantial periods of time during consumption, would seem to make an ideal product form for a portable oral care product. The art of the development and manufacture of a wide range of confectionery compositions is well known. However, the high sugar content of such confectionery compositions has been recognised as a contributory factor in poor dental health. Developments have been made to produce xe2x80x9csugar freexe2x80x9d, or non-cariogenic, confectionery which retain their organoleptic properties but which do not contribute to the formation of dental plaque. More recently research has turned to developing confectionery compositions, particularly xe2x80x9csugar freexe2x80x9d confectionery compositions, particularly chewing gum compositions, which comprise one or more oral care agents. One such example is WO 99/44436, which discloses coated chewing gum compositions which comprise materials with known oral care benefits. However, although chewing gum products have several advantages, they also have several disadvantages in that the chewing of gum is considered unsightly by some consumers and is not acceptable in certain societies. In addition, the chewing gum product format is not ideal for administering to pets and children. As such there is a need for a confectionery oral care product form, or range of forms, which are acceptable in a wide range of societies but which maintain high degrees of oral care efficacy, particularly anti-plaque and anti-calculus efficacy.
The use of polyphosphate in confectionery compositions has been reported in the art. Examples include EP 309,414 which discloses chewing gum compositions comprising gum base and an anti-tartar active selected from polyphosphate, citrates and malates; U.S. Pat. No. 4,908,211 which discloses chewing gum comprising a sanguinarine and optionally a polypyrophosphate; U.S. Pat. No. 5,702,687 which discloses chewing gum compositions optionally comprising pyrophosphate or polyphosphate and U.S. Pat. No. 4,151,270 which discloses chewing gum compositions optionally comprising tripolyphosphate. Whilst the teaching of the prior art provide useful teachings as to the development of chewing gum compositions comprising short chain polyphosphates they do not teach how to develop a wide range of confectionery compositions comprising polyphosphate with a chain length of 3 or greater such that the polyphosphate remains stably formulated within the composition and has the desired anti-calculus efficacy when the composition is consumed. There also remains a need to successfully formulate confectionery compositions comprising metal cations, which have effective and long lasting oral malodour control benefits.
Surprisingly it has now been found that, when an oral composition is prepared comprising polyphosphate with an average anion chain length of greater than or equal to 3; a first metal cation, less than 10% water wherein the ratio of polyphosphate to metal cation is in the range of from about 10:1 to about 1:1, that a composition is obtained which has effective and long lasting anti-plaque and oral malodour benefits. In addition it has been found that such compositions provide surface conditioning effects such that the surfaces of the oral cavity assume a remarkable cleaning impression and positive mouth feel characteristics for extended periods of time during and following use thus increasing the consumer noticeability of the dental benefits.
Whilst not wishing to be bound by theory it is believed that when a composition is formulated comprising a polyphosphate material with a chain length of greater than or equal to 3 in combination with a metal cation, the cations can be complexed by the polyphosphate which reduces their malodour efficacy. However by ensuring that the ratio of metal cation to polyphosphate is in the range of from about 10:1 to 1:1 the level of uncomplexed metal cation remains high enough to retain the oral malodour benefit. In addition it is believed that this control of complexation also results in sufficient metal cation to be complexed such that the product does not have an unpleasant astringent taste as is common in such materials. In addition the long chain polyphosphates modify the surface hydrophilic and hydrophobic properties of the mucosal and tooth surfaces which result in the surface conditioning effect experienced by the user. Furthermore it has been surprisingly found that when the composition comprises less than 10% water that the long chain polyphosphate, which is very susceptible to hydrolysis, remains stably formulated within the composition and therefore retains its anti-calculus efficacy. It is believed that this is because the polyphosphate is added as a dry material which is not solublised, and therefore is unable to hydrolyse, in the composition due to the low level of water. This low level of water also enables the different properties of metal salts with different solubilities to be exploited leading to a controlled release effect of the metal cations.
It is also believed that in such compositions metal cations are easily complexed by the polyphosphate material thus reducing their malodour efficacy. However, in the compositions of the present invention, by ensuring that the ratio of metal cation to polyphosphate is in the range of from about 10:1 to 1:1 the level of uncomplexed metal cation remains high enough to retain the oral malodour benefit. In addition it is believed that this control of complexation also results in sufficient metal cation to be complexed such that the product does not have an unpleasant astringent taste as is common in such materials. It is believed that these effects can be further enhanced by using a mixture of one or more metal cations which can also help to overcome the often low regulatory limits for any given metal cation. In addition, the metal cations are thought to exhibit their oral malodour effect by complexing with the volatile malodour producing compounds to provide a long lasting bad breath reduction. Finally, it is believed that the metal cations interact with the oral microbes by inhibiting the cell activity and eventually killing the organisms thus further reducing oral malodour and plaque. By using the metal cations in combination with polyphosphate the metal cation polyphosphate complex forms in equilibrium with the free materials. This acts as a slow release vehicle for the metal cations thus prolonging the effect of the metal cation action on the microbes in the oral cavity. By using a combination of metal cations it is again believed that this effect can be enhanced.
It is an object of this invention to provide low water portable oral care compositions which comprise polyphosphate materials and a metal cation to provide a product with combined and long lasting anti-calculus and oral malodour control benefits. It is a further object of this invention to provide a composition that provides improved intra-oral cleaning impression and smooth tooth surface impression to enhance the noticeability of the oral care benefit. It is another object of this invention to provide oral compositions with reduced astringency. Finally it is an object of this invention to provide compositions that are suitable for use by adults, children and pets. These and other objects of the present invention will become readily apparent from the detailed description that follows.
A confectionery composition comprising:
(i) a polyphosphate material with an average anion chain length of greater than or equal to 3;
(ii) greater than about 10 ppm of a first metal cation selected from the metals of groups 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 of the periodic table;
(iii) less than about 10% water; and
(iv) a suitable confectionery carrier material
wherein the ratio of polyphosphate anion to metal cation is in the range of from about 10:1 to about 1:1.
While the specification concludes with claims, which particularly point out and distinctly claim the invention, it is believed the present invention will be better understood from the following description.
All documents cited are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.
Herein, xe2x80x9ccomprisingxe2x80x9d means that other steps and other ingredients which do not affect the end result can be added. This term encompasses the terms xe2x80x9cconsisting ofxe2x80x9d and xe2x80x9cconsisting essentially ofxe2x80x9d.
All percentages and ratios used herein are by weight of the total composition and all measurements made are at 25xc2x0 C., unless otherwise designated.
The term xe2x80x9csafe and effective amountxe2x80x9d as used herein means an amount of a compound, component, or composition sufficient to significantly induce a positive benefit, but low enough to avoid serious side effects, i.e. to provide a reasonable benefit to risk ratio, within the scope of sound medical judgement.
The term xe2x80x9corally activexe2x80x9d as used herein means a material that provides either a cosmetic, prophylactic or therapeutic benefit within the oral cavity.
The term xe2x80x9cconfectioneryxe2x80x9d as defined herein means a solid, gum, gum-like, or glassy composition optionally having a liquid centre filling and/or optionally coated which comprises greater than about 25% sugar or sugar alcohol. Such compositions usually have a sweet taste. Examples of confectionery products include, but are not limited to, breath mints, low boiled candy, chewing gum, hard boiled candy, coated candy, lozenges, oral pasta, pressed mints, throat drops and the like.
The term xe2x80x9cchewing gumxe2x80x9d as defined herein means a confectionery composition which is suitable for chewing and which comprises 2% or greater, by weight of the composition, of elastomer.
The term xe2x80x9celastomerxe2x80x9d as defined herein means a non-digestible polymeric material, or mixture of materials, such as the materials typically used in chewing gum compositions.
The term xe2x80x9ccrunchyxe2x80x9d as defined herein means that the product has a texture such that has a firm and slightly gritty texture and which produces a slight cracking noise upon consumption. It is preferred that the compositions have a texture of granulated sugar.
The term xe2x80x9csurface conditioningxe2x80x9d as defined herein means creating a hydrophilic tooth surface immediately after treatment; and maintaining these effects for extended periods of time after use.
Active and other ingredients useful herein may be categorised or described herein by their cosmetic and/or therapeutic benefit or their postulated mode of action. However, it is to be understood that the active and other ingredients useful herein can in some instances provide more than one therapeutic and/or cosmetic benefit or operate via more than one mode of action. Therefore, classifications herein are made for the sake of convenience and are not intended to limit an ingredient to the particularly stated application or applications listed.
The elements of the compositions and methods of the present invention are described in more detail below.
Polyphosphate
Compositions of the present invention comprise a polyphosphate material, preferably comprise greater than about 1%, preferably from about 1.5% to about 50%, more preferably from about 2% to about 15%, even more preferably from about 3% to about 12%, and most preferably from about 5% to about 10%, by weight, of polyphosphate salt.
Polyphosphate is a widely used term, which relates to phosphate anions which have been polymerised by dehydration to form a polymer of the phosphate anion. The polyphosphates can exist as linear or cyclic materials or mixtures thereof. It is preferred that the polyphosphates are linear materials comprising only low levels of cyclic materials. Polyphosphates are also characterised by the average anion chain length of the polymer anion. For the purposes of this invention the polyphosphates referred to are those with an average anion chain length of 3 or greater. It is preferred that the polyphosphates have an average anion chain length of from about 3 to about 40, preferably of from about 6 to about 30; more preferably of from about 10 to about 25 and even more preferably of from about 18 to about 25, and mixtures thereof. Furthermore polyphosphates exist as salts. It is preferred that the polyphosphate is an alkali metal salt or mixtures thereof, preferably a sodium or potassium salt or mixtures thereof and more preferably a sodium salt.
Polyphosphates with an average anion chain length of greater than four usually occur as glassy materials. As defined herein a xe2x80x9cglassyxe2x80x9d material is one which is amorphous. Preferred in this invention are the linear xe2x80x9cglassyxe2x80x9d polyphosphates having the formula:
XO(XPO3)nX
wherein X is sodium, potassium, or hydrogen and n averages greater than or equal to 6 or mixtures thereof. Such polyphosphates are manufactured by FMC Corporation and are commercially known as Sodaphos (n≈6), Hexaphos (n≈13), and Glass H (n≈21). Hexaphos and Glass H are preferred with Glass H being the most preferred polyphosphate. These polyphosphates may be used alone or in combination. A broad range of phosphates and their sources are described in Kirk and Othmer, Encyclopedia of Chemical Technology, Fourth Edition, Volume 18, Wiley-Interscience Publishers (1996).
It may be desirable to have a sustained release of the polyphosphate agent from the confectionery composition. This may be accomplished by incorporating into the composition a further polyphosphate material, particularly a divalent cationic salt such as a calcium salt, which has a lower aqueous solubility than the major polyphosphate material. This can be used to tailor the release rate of polyphosphate to a required profile. By weight percent, the polyphosphate of lower solubility is generally present in no more than half, preferably no more than a quarter of the level of the more soluble material. For example, the cationic material lower solubility polyphosphate is typically present in an amount of up to about 10%, preferably from about 0.05% to about 5%, and more preferably from about 0.1% to about 3%, by weight of the composition.
Polyphosphates such as those described not only have an anti-calculus benefit but they also provide surface conditioning effects to the teeth and other surfaces of the oral cavity. The surface conditioning effects include the effective desorption of portions of undesirable pellicle proteins; creating a hydrophilic tooth surface immediately after treatment; and maintaining these effects for extended periods of time after use. These effects result in a clean feeling, which lasts beyond consumption of the confectionery product itself and further contributes to the consumer experience.
The surface conditioning effects on a subject""s teeth and oral mucosa can be measured in vivo. These measurements include consumer responses on questions concerning clean teeth and smooth teeth. The effect of creating a hydrophilic surface can be measured in terms of a relative decrease in water contact angles on air dried tooth and mucosal surfaces according to a method disclosed by Baeir et al xe2x80x9cBiophysical Modeling of Acquired Pellicle Formation on Substrata of Varying Surface Energiesxe2x80x94an in vivo studyxe2x80x9d, Caries Research, 1984, 18:408-415. The overall surface conditioning effect can also be measured by quantitative consumer studies. The surface measurements are recorded in triplicate on two separate teeth and on two separate positions on the gingival surfaces.
Metal Cation
Compositions of the present invention comprise greater than about 10 ppm of a first metal cation. The metal cation is selected from the metals of group 5 (V, Nb, Ta); group 6 (Cr, Mo, W); group 7 (Mn, Tc, Re); group 8 (Fe, Ru, Os); group 9 (Co, Rh, Ir); group 10 (Ni, Pd, Pt); group 11 (Cu, Ag, Au); group 12 (Zn, Cd, Hg); group 14 (Ge, Sn, Pb); group 16 (Se, Te, PO); and mixtures thereof. Preferably the metal cation is selected from any monovalent or divalent cation selected from the group consisting of zinc, manganese, copper, iron, cobalt, silver, selenium, tin and vanadium; preferably from the group consisting of zinc, manganese, copper, iron, silver, and tin; more preferably from the group consisting of zinc, copper, silver and tin and most preferably from the group consisting of zinc and tin. For chewing gum compositions it is preferred that the metal cation is not selected from the group consisting of zinc or tin alone but either one of these cations in combination with at least one further cation.
A wide variety of metal cation salts are useful in the present invention. These include so called xe2x80x9cwater-insoluble saltsxe2x80x9d which have a solubility of less than about 0.5 g per 100 ml at 25xc2x0 C. and xe2x80x9cwater soluble saltsxe2x80x9d which have a solubility of greater than or equal to about 0.5 g per 100 ml at 25xc2x0 C. It is also possible to use mixtures of these salts. Such mixtures can have several advantages in the compositions of the present invention since they are likely to have different complexing properties with the polyphosphate anions. In addition they have different release rates in the saliva and can therefore act to provide controlled release profiles. Examples of salts that are suitable for use herein include acetate, ammonium sulphate, bromide, chloride, chromate, citrate, dithionate, fluorosilicate, tartrate, fluoride, formate, iodide, nitrate, phenol sulphate, salicyclate, sulphate, gluconate, succinate, glycerophosphate, lactate and mixtures thereof; preferred are acetate, bromide, chloride, citrate, dithionate, tartrate, fluoride, formate, iodide, nitrate, sulphate, gluconate, succinate, lactate and mixtures thereof; and more preferred are acetate, chloride, citrate, sulphate, gluconate, succinate, lactate and mixtures thereof. If stannous chloride is used it may be advantageous to premix the stannous chloride with sodium gluconate prior to incorporating the salt in the composition since this can help to stabilise the stannous ions. When the compositions are a chewing gum it is preferred that the zinc lactate salt is not used. Furthermore for chewing gum compositions it is preferred that the tin fluoride salt is not used.
It is important that compositions of the present invention comprise levels of the metal cation, and its salts, are controlled such that the composition complies with the local regulatory standards. These standards vary from one material to another and also from one country to another but would be known to one skilled in the art.
Compositions of the present invention comprise greater than 10 ppm, preferably greater than 15 ppm, more preferably greater than 20 ppm, even more preferably greater than 25 ppm of the orally active metal cation. Compositions of the present invention preferably comprise from about 0.001% to about 5%, preferably from about 0.01% to about 2%, more preferably from about 0.1% to about 1% and most preferably from about 0.1% to about 0.5%, by weight of the composition, of metal salt comprising the orally active metal cation. It is highly preferred that if the composition is a chewing gum composition and comprises zinc lactate salt, tin fluoride salt or mixtures thereof that these salts are present at a level of greater than 1%, by weight of the composition.
When a metal cation is incorporated into compositions of the present invention, which additionally comprise polyphosphate, the additional benefit of reducing the astringency of the metal cations within the composition is obtained thus improving the taste. In order to maximise this benefit the molar ratio of polyphosphate anion to the total level of metal cation should be in the range of from about 10:1 to about 1:1, preferably from about 5:1 to about 1:1, preferably from about 3:1 to about 1:1. If more than one metal cation is used then the ratio should be taken using the total combined level of metal cation. As used herein the term xe2x80x9cpolyphosphate anionxe2x80x9d refers to a single anion regardless of chain length. The level of polyphosphate anion should be calculated by assuming that all of the polyphosphate material has the chain length of the average anion chain length of the material as quoted by the manufacturer.
If more than one metal cation is used it is preferred that the molar ratio of the first metal cation to the second metal cation should be in the range of from about 50:1 to about 1:50, preferably of from about 20:1 to about 1:20 and more preferably of from about 10:1 to 1:10. This maximises the benefits of using two metal cations. Finally for chewing gum compositions it is highly preferred that if the preferred orally active metal cation is a zinc salt, a tin salt and mixtures thereof that the salt is used in combination with a second oral malodour control agent. This further oral malodour control agent can be selected from the group comprising anti-microbial agents, natural extracts, essential oils or absorbents and these elements are discussed later in the application. The use of a further agent in combination with the zinc or tin salt is highly preferred in chewing gum compositions due to the synergistic effects of the two materials working together leading to improved oral malodour control.
Water
Compositions of the present invention comprise less than about 10%, preferably less than about 8%, more preferably less than about 5%, even more preferably less than about 3%, and most preferably less than about 2%, by weight of the composition, water. The low levels of water are required in order to ensure that the polyphenol components of the plant extracts are not oxidised and, if included, any long chain polyphosphates are not hydrolysed in the final composition.
Water used in the preparation of commercially suitable compositions should preferably be of low ion content and free of organic impurities. The amount of water in a composition should be considered to be not only that added as free water, but also water which is introduced with other materials, such as with sorbitol, silica, surfactant solutions and/or colour solutions. Furthermore the amount of water should be considered by weight of the final composition as a whole including coat and/or filling, where appropriate.
Confectionery Carrier Material
Compositions of the present invention are confectionery compositions including chewing gum. Suitable physical forms include sticks, dragees, chicklets, and batons. Although the exact ingredients for each product form will vary from product to product, the specific techniques will be known by one skilled in the art. However there are some general ingredients which are common to all product forms and these are discussed in more detail below. Preferred product forms are pressed tablets, low boiled candy, hard boiled candy and chewing gum which are readily formulated with less than about 10%, by weight of the composition, water.
Confectionery compositions of the present invention comprise a carrier material. The carrier materials vary depending on the type of confectionery used and would be well known to one skilled in the art. The carrier material can be chosen from chewable or non chewble materials. It is referred that the compositions comprise at least 10% chewable material. The chewable material can be selected from gums including agar agar gum, gelatine etc; low boiled sugar candy base and gum base materials. It is preferred that the carrier material for compositions of the present invention are not in the form of a whippable or aerated emulsion. Hard and low boiled candy carrier, pressed tablets and the like usually comprise greater than about 70% bulk sweetener including suitable sugar and sugar syrups including cariogenic and non-cariogenic materials. Low boiled candies can also comprise butter to form chewable toffee. For jelly and gum drop compositions the carrier comprises greater than about 25% bulk sweetener and additionally comprise gums including gum arabic, gelatine, agar agar powder and the like.
Compositions of the present invention are preferably in the form of a chewing gum. As such it is preferred that the compositions comprise greater than about 10%, preferably greater than about 15%, more preferably greater than about 20% and most preferably greater than about 25% and up to about 75%, by weight of the composition, of gum base. The gum base comprises a carrier material, or mixture of carrier materials, selected from elastomers, resins or waxes. The gum base carrier materials are water insoluble materials which are typically not released in the mouth. Such materials include:
(i) Elastomers and Elastomer Solvents
Compositions of the present invention preferably comprise an elastomer, or mixture of several different elastomers. Elastomeric materials are generally known in the art but illustrative examples include styrene-butadiene rubber (SBR); synthetic gums; polyisobutylene and isobutylene-isoprene copolymers; natural gums; chicle; natural rubber; jelutong; balata; guttapercha; lechi caspi; sorva; and mixtures thereof. Compositions of the present invention preferably comprise from about 2% to about 30%, more preferably from about 5% to about 25%, by weight, of elastomer. These levels are determined by the desired final texture of the chewing gum since when the total level of elastomer is below about 2% the base composition lacks elasticity, chewing texture, and cohesiveness whereas at levels above about 30% the formulation is hard, rubbery and maintains a tight chew.
Elastomer solvents are also preferably present in compositions of the present invention since they aid softening of the elastomer component. Preferred examples of elastomer solvents for use herein include the pentaerythritol ester of partially hydrogenated wood rosin, pentaerythritol ester of wood rosin, glycerol ester of partially dimerized rosin, glycerol ester of polymerised rosin, glycerol ester of tall oil, wood or gum rosin, glycerol ester of partially hydrogenated rosin, methyl ester of partially hydrogenated rosin, and mixtures thereof. Compositions of the present invention preferably comprise from about 2% to about 50%, more preferably from about 10% to about 35%, by weight, of elastomer solvent.
(ii) Resins and Waxes
Resins are an optional, but desirable, ingredient of chewing gum compositions herein. They serve to plasticise the gum base. Suitable resins include polyvinyl acetate (PVA); terpene resins, including polyterpene and polymers of alpha-pinene or beta-pinene; and mixtures thereof. Such compositions preferably comprise from about 3% to about 25%, preferably from about 5% to about 20%, by weight, of resin.
The chewing gum compositions may also include one or more waxes. Suitable waxes include paraffin wax; microcrystalline wax; Fischer-Tropsch paraffin; natural waxes such as candellilla, carnauba and beeswax; polyolefin waxes such as polyethylene wax; and mixtures thereof. Compositions comprise up to about 25%, preferably from about 5% to about 20%, by weight, of wax.
Confectionery compositions of the present invention can be centre filled. Such products preferably comprise from about 60% to about 95%, more preferably from about 75% to about 85% of an edible shell and from about 5% to about 40%, preferably from about 15% to bout 25%, by weight of the composition, of an edible filling. It is possible that centre filled confectionery composition can comprise an oral care active in the edible shell and or a different oral care active, or mixture of actives, in the edible filling. In addition the composition can comprise different flavouring agents in the shell and the filling.
Compositions of the present invention may comprise one or more crunchy solid particles dispersed throughout the carrier material. The crunchy preferably particle has a minimum particle size such that the particles are retained by a 0.1 mm mesh, preferably a 0.112 mm mesh, more preferably a 0.16 mm mesh, even more preferably a 0.18 mm mesh and most preferably a 0.2 mm mesh wherein the meshes are selected from the DIN 4188 mesh series. Furthermore the particle preferably has a maximum particle size such that it passes through a 2 mm mesh, preferably a 1 mm mesh, more preferably an 0.8 mm mesh, even more preferably a 0.5 mm mesh and most preferably a 0.4 mm mesh, again wherein the meshes are selected from the DIN 4188 mesh series. The solubility of the particle is preferably at least 1 g per 100 ml at 25xc2x0 C., more preferably at least 5 g, even more preferably at least 8 g and most preferably at least 15 g per 100 ml at 25xc2x0 C. Finally it is preferred that the particulate material has a hardness of greater than 1, preferably greater than 2 on the Mohs hardness scale. The particle size, solubility and hardness properties confer a crunchy texture to the confectionery itself. Such particles can be present as solid forms of one of the oral care actives outlined above, in the case where the oral care active is a solid, or can be a further particle such as sugar crystals, dried fruits, nuts, etc. The crunchy texture can be used to reinforce the oral care benefits to the consumer. Different crunchy textures can be obtained by milling the particles to the desired size or by blending different commercial grades of particles to achieve the desired crunch. It is preferred the that crunchy sensation remains consumer noticeable for at least 1 minute 30 seconds, preferably for at least 2 minutes and more preferably for at least 2 minutes 30 seconds. However it is also preferred that the crunchy texture has disappeared by 5 minutes, preferably by 4 minutes so that the material does not abrade the dentin or so that the product does not have a gritty residue.
Furthermore the confectionery compositions of the present invention can also be coated. The outer coating may be hard or crunchy. Typically, the outer coating will essentially consist of sorbitol, maltitol, xylitol, isomalt, and other crystallisable polyols. Furthermore the coating will typically consist of several opaque layers, such that the confectionery core is not visible through the coating itself, which can optionally be covered with a further one or more transparent layers for aesthetic, textural and protective purposes. The outer coating may also contain small amounts of water and gum arabic. A polyol coating can be further coated with wax. The coating is applied in a conventional manner by successive applications of a coating solution, with drying in between each coat, as described in WO99/44436. As the coating dries it usually becomes opaque and is usually white, though other colorants may be added. A polyol coating can be further coated with wax. The coating can further comprise coloured flakes or speckles. If the composition comprises a coat it is possible that one or more of the oral care actives can be dispersed throughout the coat. This is especially preferred if one or more oral care active is incompatible in a single phase composition with another of the actives.
Balance of the Composition
Compositions of the present invention preferably comprise safe and effective levels of one or more additional components. Such materials are well known and are readily chosen by one skilled in the art based on the oral care, physical and aesthetic properties desired for the compositions being prepared. Examples of such materials include, but are not limited to fats, solvents, waxes, emulsifiers, softeners, bulking agents, cationic material, buffers, whitening agents, alkali metal bicarbonate salts, thickening materials, humectants, water, surfactants, titanium dioxide, flavouring agents, colouring agents, and mixtures thereof. Those ingredients most commonly used are described in more detail below.
Oral Care Active
Compositions of the present invention comprise an oral care active selected from the group consisting of anti-calculus agents; anti-plaque agents; desensitising agents; fluoride ion source; oral malodour control agents; H2 antagonists; and mixtures thereof. Preferably the oral care active is selected from the group consisting of anti-calculus agents; the group of anti-plaque agents; the group of desensitising agents; oral malodour control agents; more preferably the oral care active is an anti-calculus agent; more preferably the oral care active is polyphosphate. It is not intended that the actives listed in groups below are mutually exclusive and a single active may be included in compositions of the present invention to have several effects.
Compositions of the present invention preferably comprise from about 0.01% to about 50%, more preferably from about 0.1% to about 15%, even more preferably from about 0.25% to about 10%, and most preferably from about 0.5% to about 7%, by weight, of oral care active.
Anti-Calculus Agents:
Anti-calculus agents known for use in dental care products include phosphate, pyrophosphate, polyphosphate (discussed above), phosphonate, polyphosphonate and mixtures thereof. Pyrophosphates are among the best known for use in dental care products. The pyrophosphate salts useful in the present compositions include the dialkali metal pyrophosphate salts, tetra-alkali metal pyrophosphate salts and mixtures thereof in their unhydrated as well as hydrated forms are the preferred species. Disodium dihydrogen pyrophosphate (Na2H2P2O7), tetrasodium pyrophosphate (Na4P2O7), and tetrapotassium pyrophosphate (K4P2O7) and mixtures thereof. The pyrophosphate salts are described in more detail in Kirk and Othmer, Encyclopedia of Chemical Technology, 3rd Edition, Volume 17, Wiley Interscience Publishers (1982). Additional anti-calculus agents include polyacrylates and other polycarboxylates such as those disclosed in U.S. Pat. No. 3,429,963 issued to Shedlovsky on Feb. 25, 1969 and U.S. Pat. No. 4,304,766 issued to Chang on Dec. 8, 1981; and U.S. Pat. No. 4,661,341 issued to Benedict and Sunberg on Apr. 28, 1987; polyepoxysuccinates such as those disclosed in U.S. Pat. No. 4,846,650 issued to Benedict, Bush and Sunberg on Jul. 11, 1989; ethylenediaminetetraacetic acid as disclosed in British Patent No 490,384 date Feb. 15, 1937; nitrilotriacetic acid and related compounds as disclosed in U.S. Pat. No. 3,678,154 issued to Widder and Briner on Jul. 18, 1972; polyphosphonates as disclosed in U.S. Pat. No. 3,737,533 issued to Francis on Jun. 5, 1973; U.S. Pat. No. 3,988,443 issued to Ploger, Schmidt-Dunker and Gloxhuber on Oct. 26, 1976 and U.S. Pat. No. 4,877,603 issued to Degenhardt and Kozikowski on Oct. 31, 1989. Anticalculus phosphates include potassium and sodium pyrophosphates; sodium tripolyphosphate; diphosphonates such as ethane-1-hydroxy-1,1-diphosphonate, 1-azacycloheptane-1, 1-diphosphonate, and linear alkyl diphosphonates; linear carboxylic acids; and sodium zinc citrate and other soluble zinc salts.
Anti-Plaque Agents:
Anti-plaque agents include anti-plaque agents and flouride ion sources. Anti-plaque agents are any substances which inhibit the accumulation of bacterial deposits on the surfaces of the oral cavity. Examples include xylitol and other anti-microbial agents.
Fluoride Ion Source:
Application of fluoride ions to dental enamel serves to protect teeth against decay. A wide variety of fluoride ion yielding materials can be employed as sources of soluble fluoride in the present compositions. Examples of suitable fluoride ion yielding materials are found in U.S. Pat. No. 3,535,421, Oct. 20, 1970 issued to Briner et al. and U.S. Pat. No. 3,678,154 Jul. 18, 1972 issued to Widder et al. Preferred fluoride ion sources for use herein include sodium fluoride, potassium fluoride, stannous fluoride, ammonium fluoride and mixtures thereof. Sodium fluoride is particularly preferred. Preferably the present composition provide from about 50 ppm to about 10,000 ppm, more preferably from about 100 ppm to about 3000 ppm of fluoride ions.
Desensitising Agents:
Desensitising agents, or anti-pain agents, can also be present in the oral care compositions or substances of the present invention. Such agents may include, but are not limited to, strontium chloride, potassium nitrate, natural herbs such as gall nut, Asarum, Cubebin, Galanga, scutellaria, Liangmianzhen, Baizhi, etc. Analgesics, including low levels of non-steroidal anti-inflammatory agents, such as ketorolac, flurbinprofen, ibuprofen, naproxen, indomethacin, aspirin, ketoprofen, piroxicam and meclofenamic acid, may also be used as desensitising agents.
Oral Malodour Control Agents:
Oral malodour control agents include a wide variety of materials. The most commonly used are antimicrobial agents can also be present in the oral care compositions or substances of the present invention. Such agents may include, but are not limited to, 5-chloro-2-(2,4-dichlorophenoxy)-phenol, commonly referred to as triclosan, and described in the Merck Index, 11th Edition, (1989), pp1529 (entry no 9573) in U.S. Pat. No. 3,506,720, and in European Patent Application No 0,251,591 of Beecham Group, Plc, published Jan. 7, 1988; phthalic acid and its salts including, but not limited to those disclosed in U.S. Pat. No. 4,994,262 published Feb. 19, 1991, preferably magnesium mono-potassium phthalate, chlorhexidine (Merck Index, no 2090); alexidine (Merck Index, no 222); hexetidine (Merck Index, no 4624); sanguinarine (Merck Index, no 8320); benzalkonium chloride (Merck Index, no 1066); salicylanilide (Merck Index, no 8299); domiphen bromide (Merck Index, no 3411); cetylpyridinium chloride (CPC) (Merck Index, no 2024); tetradecylpyridinium chloride (TPC); N-tetradecyl-4-ethylpyridinium chloride (TDEPC); octenifine; delmopinol; octapinol; and other piperidine derivatives; nicin preparations; zinc/stannous ion agents; antibiotics such as augmentin, amoxicilline, tetracycline, doxycycline, minocycline, and metronidazole; and analogues and salts of the above; methyl salicyclate; and mixtures of all of the above.
A second class of materials are the anti-bacterial natural plant extracts. These extracts include extracts obtained from any part of the plant including the leaf, stem, bark, pulp, seed, flesh, juice, root and mixtures thereof. It is preferred that the extract is obtained from the leaf, pulp and seed, more preferably from the leaf or seed. Many different plants, or parts of plants, can be used to provide these extracts including tea, especially green tea, magnolia, gold thread, honeysuckle, grape, bergamot, grapefruit, orange, lemon, tangerine, mandarin, satsuma, clementine, lime, and mixtures thereof; preferably from grape, grapefruit and mixtures thereof. Such extracts comprise a wide variety of biologically active materials. These include anthocyanins, flavanols, hydrolysable tannins, alkaloids, lipids, carbohydrates, simple sugars, protein and amino acids, alcohols, polyphenols, organic acids and mixtures thereof. Essential oils are also known to have anti-bacterial properties. These include thymol, geraniol, carvacrol, hinokitiol, eucalyptol, catechol (particularly 4-allyl catechol) and mixtures thereof. It is preferred that compositions of the present invention comprise from about 0.0001% to about 30%, preferably from about 0.001% to about 15%, more preferably from about 0.01% to about 10%, even more preferably from about 0.1% to about 5% and most preferably from about 0.25% to about 3%, by weight of the composition, of extract.
Compositions of the present invention may optionally comprise zinc phytate in combination with natural extracts. The zinc phytate is believed to enhance the polyphenol breath protection efficacy and increase the stability of the polyphenol extract. Compositions of the present invention preferably comprise from about 0.1% to about 10%, more preferably from about 0.5% to about 5% and most preferably from about 1% to about 3%, by weight of the composition, of zinc phytate.
Another class of oral malodour control agents include absorbents. These are used to absorb, adsorb, bind or otherwise complex the volatile oral malodour materials. Examples of such agents include talc, mushroom extract, zeolite, cyclodextrin, silica shell and mixtures thereof. Such materials are preferably used at a level of from about 0.5% to about 10%, preferably from about 1% to about 5%, by weight of the composition.
H-2 Antagonists:
Histamine-2 (H-2) receptor antagonist compounds (H-2 antagonists) may be used in the oral care compositions of the present invention. As used herein, selective H-2 antagonists are compounds that block H-2 receptors, but do not have meaningful activity in blocking histamine-1 (H-1) receptors. Selective H-2 antagonists include those disclosed in U.S. Pat. Nos. 5,294,433 and 5,364,616 Singer et al., issued Mar. 15, 1994 and Nov. 15, 1994 respectively and assigned to Procter and Gamble, wherein the selective H-2 antagonist is selected from the group consisting of cimetidine, etintidine, ranitidine, ICIA-5165, tiotidine, ORF-17578, lupitidine, donetidine, famotidine, roxatidine, pifatidine, lamtidine, BL-6548, BMY-25271, zaltidine, nizatidine, mifentidine, BMY-52368, SKF-94482, BL-6341A, ICI-162846, ramixotidine, Wy-45727, SR-58042, BMY-25405, loxtidine, DA-4634, bisfentidine, sufotidine, ebrotidine, HE-30-256, D-16637, FRG-8813, FRG-8701, impromidine, L-643728 and HB-408. Particularly preferred is cimetidine (SKF-92334), N-cyano-Nxe2x80x2-methyl-Nxe2x80x3-(2-(((5-methyl-1H-imidazol-4-yl)methyl)thio)ethyl)guanidine:
Cimetidine is also disclosed in the Merck Indes, 11th editions (1989), p354 (entry no 2279), and Physicians"" Desk Reference, 46th edition (1992), p2228. Related preferred H-2 antagonists include burimamide and metiamide.
Antioxidants:
Antioxidants are generally recognised as useful in compositions such as those of the present invention. Antioxidants are disclosed in texts such as Cadenas and Packer, The Handbook of Antioxidants, (copyright) 1996 by Marel Dekker, Inc. Antioxidants that may be included in the oral care compositions of the present invention include, but are not limited to, Vitamin E, ascorbic acid, Uric acid, carotenoids, Vitamin A, flavenoids and polyphenols, herbal antioxidants, melatonin, aminoindoles, lipoic acids and mixtures thereof.
Teeth Colour Modifying Substances:
Teeth colour modifying substances may be considered among the oral care actives useful in the present invention. These substance are suitable for modifying the colour of the teeth to satisfy the consumer such as those listed in the CTFA Cosmetic Ingredient Handbook, 3rd Edition, Cosmetic and Fragrances Association Inc., Washington D.C. (1982), incorporated herein by reference. Specific examples include talc, mica, magnesium carbonate, calcium carbonate, magnesium silicate, aluminium magnesium carbonate, silica, titanium dioxide, zinc oxide, red iron oxide, brown iron oxide, yellow iron oxide, black iron oxide, ferric ammonium ferrocyanide, manganese violet, ultramarine, nylon powder, polyethylene powder, methacrylate powder, polystyrene powder, silk powder, crystalline cellulose, starch, titanated mica, iron oxide titanated mica, bismuth oxychloride, and mixtures thereof. Typical pigment levels from about 0.05% to about 20%, preferably from about 0.1% to about 15% and most preferably from about 0.25% to about 10%, by weight, of the composition.
Compositions for use herein may also comprise materials that remove or bleach intrinsic or extrinsic stains on or in tooth surfaces. Such substance are selected from the group consisting of the peroxides, metal chlorites, perborates, percarbonates, peroxyacids, persulphates, and combinations thereof. Suitable peroxide compounds include hydrogen peroxide, urea peroxide, calcium peroxide, carbamide peroxide and mixtures thereof. Suitable metal chlorites include calcium chlorite, barium chlorite, magnesium chlorite, lithium chlorite, sodium chlorite and potassium chlorite. Additional bleaching substances may be hypochlorite, and chlorine dioxide. A preferred percarbonate is sodium percarbonate. Preferred persulphates are oxones. The level of these substances is dependent on the available oxygen or chlorine. This level is generally used in compositions of the present invention at levels from about 0.1% to about 35%, preferably from about 1% to about 25% and most preferably from about 5% to about 10%, by weight of the composition.
Nutrients
Nutrients may improve the condition of the oral cavity and can be included in the oral care compositions or substances of the present invention. Nutrients include minerals, vitamins, oral nutritional supplements, enteral nutritional supplements, herbal supplements, natural extracts and mixtures thereof as disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St Louis, Mo., (copyright)1997. Minerals that can be included with the compositions of the present invention include calcium, phosphorus, fluoride, zinc, manganese, potassium and mixtures thereof. Vitamins can be included with minerals or used separately. Vitamins include Vitamins C and D, thiamine, riboflavin, calcium pantothenate, niacin, folic acid, nicotinamide, pyridoxine, cyanocobalamin, para-aminobenzoic acid, bioflavonoids, and mixtures thereof. Fish oil contains large amounts of Omega-3 (N-3) polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid.
Sweeteners
Two main types of sweeteners exist; bulk sweeteners and high intensity sweeteners. In general, the amount of sweetener used will vary depending on the sweetener and the overall desired aesthetics but levels used should be high enough such that the desired level of sweetness is achieved independent from the flavour. When bulk sweeteners are used they can also assume the role of the bulking agent or filler within the composition.
Bulk Cariogenic Sweetener:
Compositions of the present invention may comprise sweetener materials. Such materials include monosaccharides, disaccharides, polysaccharides and mixtures thereof. Examples include xylose, ribose, glucose, mannose, galactose, fructose, dextrose, sucrose, sugar maltose, fructo oligo saccharide syrups, partially hydrolysed starch, or corn syrup solids and mixtures thereof. However, such materials can often lead to the formation of cavities since they are readily metabolised by bacteria and other micro-organisms in the oral cavity. It is preferred that compositions of the present invention comprise less than about 10%, preferably less than about 5%, more preferably less than about 2%, even more preferably less than about 1%, and most preferably less than about 0.5%, by weight of the composition, of cariogenic sweetener. Compositions of the present invention may comprise 0% of a cariogenic sweetener if desired.
Bulk Non Cariogenic Sweeteners:
Compositions of the present invention preferably comprise a non-cariogenic sweetener. As used herein the term xe2x80x9cnon-cariogenicxe2x80x9d refers to sweeteners which are not able to be metabolised by oral microbes and therefore do not contribute to the formation of dental caries. It is preferred that compositions of the present invention comprise greater than about 10%, preferably greater than about 20%, more preferably greater than about 30% and most preferably greater than about 40%, by weight of the composition, of non cariogenic sweetener. Compositions of the present invention may comprise up to about 99%, by weight of the composition, of non-cariogenic sweetener.
Preferred bulk non cariogenic sweetening agents are sugar alcohols such as sorbitol, xylitol, mannitol, maltitol, isomalt, hydrogenated starch hydrolisate, insulin, and other non-cariogenic edible polyols such as glycerin and erythritol and mixtures thereof. Most preferred are non cariogenic sweeteners selected from the group consisting of maltitol, mannitol, xylitol, sorbitol, sucralose, aspartame and its salts, and mixtures thereof. In general compositions comprise from about 10% to about 80%, more preferably from about 30% to about 70%, by weight, of bulk sweetener.
High Intensity Sweeteners:
High intensity sweeteners are preferred over bulk sweeteners for use in compositions of the present invention because, for among other reasons, high intensity sweeteners may prolong the flavour of the finished gum composition during chewing. Suitable high intensity sweeteners include: dipeptide based sweeteners such as L-aspartyl-L-phenylalanine methyl ester (Aspartame) and equivalents (described in U.S. Pat. No. 3,492,131), L-xcex1-aspartyl-N-(2,2,4,4-tetramethyl-3-thietanyl)-D-alaninamide hydrate (Alitame) and the like; saccharin and its soluble salts eg sodium or calcium saccharin salts; cyclamate salts for example acesulfame-K and the like; chlorinated derivatives of sucrose such as chlorodeoxysucrose and the like; and protein based sweeteners, such as Thaumatin (talin). Compositions of the present invention preferably comprise from about 0.01% to about 2.0%, more preferably from about 0.05% to about 0.5%, by weight, of high intensity sweetener.
Bulking Agents
Bulking agents, such as fillers, can also be employed in confectionery. Suitable fillers and bulking agents are generally non-abrasive, preferably with an average particle size less than 5 xcexcm, more preferably less than 3 xcexcm and especially less than 1 xcexcm. Illustrative bulking agents include calcium carbonate or ground limestone, talc, aluminium hydroxide, alumina, aluminium silicates, dicalcium phosphate and mixtures thereof. Compositions preferably comprise up to about 50%, more preferably up to about 30%, and most preferably up to about 10%, by weight, of bulking agent.
Additional Chewing Gum Ingredients
There are several ingredients which are commonly added to chewing gum compositions and which are not commonly used in other types of confectionery. Examples of materials are listed below but this list is not to be considered limiting. Similarly such ingredients can be used in other types of confectionery if desired.
Chewing gum compositions of the present invention may also comprise plasticisers in addition to the resin component. Suitable plasticisers include glyceryl triacetate, acetylated monoglyceride, glyceryl tributyrate, ethyl laurate, ethyl acetoacetate, diethyl tartrate, ethyl or butyl lactates, diethyl malate, ethyl oleate, castor oil, succinylated monoglycerides or mixtures thereof. Glyceryl triacetate and acetylated monoglyceride are preferred. Compositions preferably comprise up to about 10%, preferably from about 0.1% to about 3%, by weight, of plasticiser.
Compositions of the present invention preferably comprise a softener or mixture of softeners which, when incorporated into the gum base, assist in modifying the texture and consistency properties. In particular, they help to soften the chew and to maintain chew softness over an extended period of time. Suitable softeners include fatty materials such as lanolin, stearic acid, sodium stearate and potassium stearate; polyhydric alcohols such as glycerine, propylene glycol, and the like; and mixtures thereof. Compositions preferably comprise up to about 30%, more preferably from about 0.1% to about 10%, by weight, of softener. In a preferred embodiment, the chewing gum composition comprises from about 0.1% to about 10%, by weight, of a fatty softener selected from stearic acid, sodium stearate, potassium stearate and mixtures thereof, preferably stearic acid.
The chewing gum compositions preferably comprise an emulsifier such as glycerol monostearate, lecithin, fatty acid monoglycerides, diglycerides, propylene glycol monostearate and mixtures thereof. Compositions comprise up to about 10%, and preferably from about 2% to about 6%, by weight, of emulsifier. Various fats can also be included in the chewing gum compositions of the present invention. Preferred fats include the hydrogenated vegetable oils such as hydrogenated palm oil, hydrogenated soybean oil, hydrogenated cotton seed oil and various other hydrogenated vegetable oils and mixtures thereof. The fats can suitably be used at a level up to about 20%, preferably from about 1% to about 10%, by weight, of the chewing gum composition.
Flavouring Agents
Compositions of the present invention can preferably comprise a flavouring agent. As used herein the term xe2x80x9cflavouring agentxe2x80x9d means those flavour essences and equivalent synthetic materials which are added to flavour the composition. The flavouring agent can also include specific materials which are added to provide a warming or cooling sensation.
Flavouring agents are well known in the art. They include synthetic flavours and or oils and or essences derived from plants, roots, beans, nuts, leaves, flowers, fruits and so forth and mixtures thereof. Examples of suitable flavours include lemon, orange, banana, grape, lime, apricot, grapefruit, apple, strawberry, cherry, chocolate, pineapple, coffee, cocoa, cola, peanut, almond, liquorice, cinnamon and the like. The amount of flavouring agent employed is normally a matter of preference but in general they are used in amounts up to about 4%, preferably from about 0.1 to about 1%, by weight of the composition.
Compositions of the present invention can optionally comprise a cooling agent and suitable materials are described in WO 97/06695. Preferred for use herein are physiological cooling agents selected from the group consisting of menthol, peppermint oil, N-substituted-p-menthane-3-carboxamides, acyclic tertiary and secondary carboxamides, 3-1-methoxy propan-1,2-diol and mixtures thereof. Particularly preferred are menthol and menthol containing oils such as peppermint oil. Cooling agents are preferably used at a level of from about 0.001 to about 5%, more preferably from about 0.05% to about 3.5%, by weight of the composition.
Compositions of the present invention can optionally comprise a warming agent. Preferred agents include those selected from the group consisting of vanillyl alcohol n-butyl ether, vanillyl alcohol n-propyl ether, vanillyl alcohol isopropyl ether, vanillyl alcohol isobutyl ether, vanillyl alcohol n-amino ether, vanillyl alcohol isamyl ether, vanillyl alcohol n-hexyl ether, vanillyl alcohol methyl ether, vanillyl alcohol ethyl ether, ginerol, shogaol, paradol, zingerone, capsaicin, dihydrocapsaicin, nodihydrocapsaicin, homocapsaicin, homodihydrocapsaicin, ethanol, isopropyl alcohol, iso-amylalcohol, benzyl alcohol, chloroform, eugenol, cinnamon oil, cinnamic aldehyde, and mixtures thereof. Warming agents are preferably used at a level of from about 0.001 to about 5%, more preferably from about 0.05% to about 3.5%, by weight of the composition.
Preparation of Compositions
The compositions of the present invention are prepared by standard techniques well known to those skilled in the art. It is preferred that the polyphosphate is not pre-dispersed in water prior to addition to the composition in order to prevent hydrolysis. If the composition comprises more than one phase, in general the different phases will be prepared separately, with materials of similar phase partitioning being added in any order. The two phases will then be combined with vigorous stirring to form the multiphase system eg an emulsion or dispersion.
Any ingredients in the formulation with high volatility, or which are susceptible to hydrolysis at high temperatures, will usually be added post mixing of the different phases with gentle stirring. Typical confectionery methods are highly suitable for manufacturing of compositions of the present invention. Finally if the products are coated confectionery compositions the coating step is conducted as a final step. The coating can be applied by panning or spray dried techniques commonly known to those skilled in the art.

Abstract: (ii) greater than about 10 ppm of a metal cation selected from the metals of groups 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 of the periodic table;

Abstract: (iii) less than about 10% water; and


Stents having a plurality of serpentine bands including a proximal end portion, a distal end portion, and a middle portion therebetween are herein disclosed. Each of the bands includes peaks and valleys. Serpentine bands of the proximal end portion are connected together in a repeating pattern of connected and unconnected peaks and valleys. Serpentine bands of the distal end portion are connected together in a repeating pattern of connected and unconnected peaks and valleys. The repeating pattern of the proximal end portion is different than the repeating pattern of the distal end portion.

A stent is a medical device introduced to a body lumen and is well known in the art. Typically, a stent is implanted in a blood vessel at the site of a stenosis or aneurysm endoluminally, by so-called "minimally invasive techniques" in which the stent in a radially reduced configuration, optionally restrained in a radially compressed configuration by a sheath and/or catheter, is delivered by a stent delivery system or "introducer" to the site where it is required. The introducer may enter the body from an access location outside the body, such as through the patient's skin, or by a "cut down" technique in which the entry blood vessel is exposed by minor surgical means.
Stents, grafts, stent-grafts, vena cava filters, expandable frameworks, and similar implantable medical devices are radially expandable endoprostheses which are typically intravascular implants capable of being implanted transluminally and enlarged radially after being introduced percutaneously. Stents may be implanted in a variety of body lumens or vessels such as within the vascular system, urinary tracts, bile ducts, fallopian tubes, coronary vessels, secondary vessels, etc. They may be self-expanding, expanded by an internal radial force, such as when mounted on a balloon, or a combination of self-expanding and balloon expandable (hybrid expandable).
Stents may be created by methods including cutting or etching a design from a tubular stock, from a flat sheet which is cut or etched and which is subsequently rolled or from one or more interwoven wires or braids.
Particular problems arise from stenosis in the superficial femoral artery (SFA). In combating problems associated with the SFA, stents can be placed therein. Any stent placed in the SFA must have a great deal of flexibility so as to cope with the repeated bending of the artery and also be resistant to fatigue.
The art referred to and/or described above is not intended to constitute an admission that any patent, publication or other information referred to herein is "prior art" with respect to this invention. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.


A method for manufacturing a radiofrequency identification device which includes a manufacturing process for an antenna which includes screen-printing turns of an electrically conductive polymer ink onto a transfer paper sheet, and then subjecting the support to heat treatment to bake and polymerize the conductive ink, connection of a chip 14, provided with contacts, to the antenna 12, lamination which includes making the transfer paper sheet integral with a layer of plastic material 16 which constitutes the support for the antenna, by hot press molding, in such a way that the screen-printed antenna and the chip are both embedded within the layer of plastic material, and removal of the transfer paper sheet.

Smart cards and tickets, and more particularly ISO format cards, have become extremely widespread in recent years. Above and beyond their use as credit cards, smart cards have become indispensable tools in many areas. This growth is largely due to the fact that, in addition to the traditional use of cards which make contact with the appropriate reader (e.g. bank and telephone cards), the new cards can be used without any physical contact with the reader.
The exchange of information between the contactless card or hybrid contact-contactless card and the associated reader is accomplished by remote electromagnetic coupling between an antenna integrated into the contactless card and a second antenna located in the reader. In order to create, store and process the information, the card is provided with a chip which is connected to the antenna. The antenna is generally located on a dielectric support made of plastic material. This ease of use has made the development of many other applications possible. For example, the development of the electronic wallet. In the transportation sector, smart cards have been developed as a means of paying highway tolls. At events, smart cards can be used by supporters as a season ticket for venues. For security applications, many companies have set up systems for staff identification based on ISO contactless smart cards.
The conventional contactless cards found on the market consist of several layers of plastic material, notably polyvinyl chloride (PVC). One of these layers constitutes the support for the antenna, and the others generally constitute the body of the card. The card's antenna is most commonly a copper wire or is chemically etched onto the card.
However, the production of such cards is relatively expensive. This is because the use of copper and etching processes are both expensive. Moreover, producing such an antenna on a PVC support necessarily entails using sophisticated—and therefore expensive—machinery.
Now, the development of contactless technology is dependent on a reduction in the manufacturing costs for such cards. One way of reducing production costs involves cheaper manufacturing methods for the antenna, notably by creating it using a screen-printing process with a conductive ink.
However, screen-printing on PVC is associated with a number of drawbacks. Furthermore, PVC exhibits poor thermomechanical properties. During the card body lamination process, material flow is significant and the antenna's shape factor is not maintained. Before lamination, when the conductive ink used to create the antenna is drying, the temperature is higher than that at which the plastic material becomes soft so there is deformation of the support which affects the antenna's electrical performance. This leads to antenna malfunction as electrical parameters (inductance and resistance) vary. Even more serious, it is not uncommon to experience antenna breakage in areas where strong sheer stresses are present. Moreover, it is impossible to replace the thermoplastic material with a thermosetting one since the latter is not amenable to hot lamination.
Another disadvantage is that, when the antenna is screen-printed onto PVC, connecting the chip to the antenna is much more difficult.

This patent is subject to a terminal disclaimer.

Method for manufacturing radiofrequency identification device using transfer paper and radiofrequency identification device produced using this method


A mandible support device comprising a structural member comprising a support component and an adhesive component. The support component is configured to extend from the head or face above the mandible to the region of the gonial angle, or from the gonial angle on a first side of a face to the gonial angle on a second side of a face, across the premaxilla region of the face. The adhesive component is configured such that the structural member can be temporarily attached to the skin.

Field of the Invention
The inventions disclosed and taught herein relate generally to a device and method supporting the human mandible; and more specifically relate to a simple, comfortable, and easy to manufacture device for the reduction or elimination of airway constriction resulting from posterior displacement of the mandible.
Background Information and Description of the Related Art.
A shift in the mandible in a posterior direction typically results in a restriction or blocking of the air passage in the throat. Such a restriction in the throat air passage may occur when an individual relaxes the muscles of the face and throat, such as occurs during sleeping or as may occur during waking activities such as endurance athletics. The relaxed muscles reduce support of the mandible, which allows the mandible to shift in a posterior direction. In turn, the shifted mandible allows soft tissue in the back of the throat to sag. The sagging soft tissue then blocks the flow of air needed for breathing.
A common example of the effect on airway resulting from mandibular displacement is snoring. A sleeping person will generally respond to the blockage of the airway by breathing harder, thereby increasing the air pressure in the airway. The increased air pressure results in a partial opening of the airway. The snoring sound is the restricted airflow vibrating the soft tissue. The snoring noise disturbs the sleep of others in the proximity of the snoring person, and the snoring person has laborious breathing that reduces the quality of sleep. Extreme cases of air passage blockage often result in a medical condition, called obstructive sleep apnea, where the quality of sleep is severely degraded and other deleterious health effects are exhibited.
There are a number of types of treatments for snoring in the prior art. These various treatments can be divided into at least two classes: surgical and mechanical. Surgical treatments include palatal implants, in which braided strands of polyester filament are injected into the snorer's soft palate, with the intention of stiffening the soft tissues and reducing snoring. Another surgical treatment is uvulopalatopharyngoplasty, which can be conducted using traditional or laser-assisted surgical techniques to shorten the soft palate and remove the snorer's uvula, enlarging the airway with the intent of reducing vibration of the soft tissues during sleep. Another surgical treatment is radiofrequency tissue ablation (somnoplasty), in which low-intensity radiofrequency signals are used to shrink tissue in the soft palate. The surgical treatments for snoring all have the risks associated with surgery, are expensive, and of uncertain effectiveness.
Mechanical treatments for snoring include continuous positive airway pressure (CPAP) devices. The user of a CPAP device wears a mask over the nose and/or mouth while sleeping. The mask is attached to an air pump that forces air through the snorer's airway to raise the air pressure inside the airway to approximately 70 to 120 Pascal above atmospheric pressure. The increased pressure functions to reduce or eliminate the airway blockage caused by the sagging soft tissue. The CPAP is generally considered to be the most reliable treatment for snoring and obstructive sleep apnea. However, the equipment is bulky and many individuals who begin using a CPAP find it uncomfortable or disruptive to sleep. Studies suggest that approximately half of the individuals who begin using a CPAP machine to treat sleep apnea cannot tolerate them and discontinue their use.
Other mechanical treatments for snoring include oral appliances. Oral appliances are form fitting dental mouthpieces that help advance the position of the tongue and soft palate with the intent of opening the airway, often by repositioning the lower mandible to jut forward into an unnatural position. Oral appliances are relatively expensive, and have a variety of sometimes-severe side effects, including jaw pain, facial discomfort, and modified tooth alignment.
Examples of such oral appliances include U.S. Pat. No. 7,832,403 issued to Halstrom on Nov. 16, 2010, in which a mandible position device is described as having a maxillary dentition engagement component and a mandibular dentition engagement component, each on opposite sides of a plane extending therebetween. An adjustable connection couples the maxillary dentition engagement component with the mandibular dentition engagement component. The adjustable connection has a first adjustment screw having a longitudinal axis perpendicular to the plane. The first and second adjustable screws are independently adjustable and structures to effect horizontal and vertical displacement, respectively, of the maxillary dentition engagement component relative to the mandibular dentition engagement component.
Other examples of such oral appliances include U.S. Pat. No. 8,613,283 issued to Hegde on Dec. 24, 2013, in which a mandibular advancement appliance is described which is secured to a subject's dentition. The appliance may adjust a portion of the subject's lower dentition relative to the upper dentition while maintaining a distance between the upper and lower dentition. The appliance may also allow for the free rotation of the lower dentition relative to the upper dentition for increased comfort. Additionally, the appliance may also be utilized with a tongue retention assembly for maintaining a position of the subject's tongue relative to the device for treating sleep disordered breathing.
A third category of mechanical devices for the reduction or prevention of snoring includes devices that are worn externally on or about the face and/or neck of the subject. Some such devices are braces and similar structures that are worn about the head and neck. For example, U.S. Pat. No. 8,695,607 issued to Hohenhorst on Apr. 15, 2014, discloses apparatus, systems, and methods to constrain and/or support tissue structures along an airway. Hohenhorst discloses apparatus, systems, and methods that externally brace tissues structures in, on, or near the neck, along the walls of the pharyngeal airway itself. The apparatus, systems, and methods mechanically support these tissue structures in, on, or near the neck in a desired orientation, biased away from the pharyngeal airway. The mechanical support that the apparatus, systems, and methods provide affirmatively resists collapse of the tissue structures in, on, or near the neck toward and into the pharyngeal airway, thereby moderating or preventing the incidence of sleep apnea. Such apparatus, systems, and methods disclosed by Hohenhorst include, for example, a full collar structure that is worn about the entire neck at the level of the larynx and including releasable fasteners so that an individual can adjust the fit and form of the collar around their neck.
Other such devices are intended to adhere to the face or neck of a subject to mechanically enlarge an airway. For example, U.S. Pat. No. 5,752,524 issued to Corcoran on May 19, 1998, discloses a device for preventing or reducing snoring. The Corcoran device includes in combination a rigid ellipsoidal support base having a concave interior surface and a convex exterior surface and an adhesive material for attaching to human epidermis layered on a predominance of the entire convex interior surface. The device is stated to be "particularly useful to prevent snoring in a sleeping human by providing a small air passage between the superior maxillary facial muscles of the face, and the superior maxilla (upper jaw bone), which allows for the intake and output of air such that the sleeping individual does not have to intake and output air through the nose. By this means, snoring is prevented, or markedly reduced."
Another example of such a device is disclosed in U.S. Pat. No. 7,793,661 issued to Macken on Sep. 14, 2010. Macken discloses an anti-snoring device that attaches to a specific area of the neck. The attachment means can be an adhesive, a clip or an implant. The device exerts a predetermined pulling force on this area of the neck, causing this area of the neck to expand outward from its normal position. This expansion opens a blockage in the throat of a sleeping person, thereby eliminating snoring and helping some people with obstructive sleep apnea.
Another example of such a device is disclosed in U.S. Pat. No. 8,188,330 issued to Beaudry on May 29, 2012. Beaudry discloses a dressing mechanism comprising a first section, a second section, and a third section. The first section and the third section each may include one side having an adhesive layer. An overlaying, non-adhesive barrier layer may be located between a portion of the adhesive layer and a first or third section. At least one of the first or third sections may further include a plurality of hook or loop members which are arranged to be fastened to corresponding hook or loop members of a hook and loop fastener. Several forms of the mechanism disclosed by Beaudry related to epidermal lifting mechanisms and methods for increasing the flow of gases into the human body and more specifically to an epidermal lifting mechanism and method for allowing more oxygen to pass through the nasal cavity thus increasing both the flow of oxygen into the lungs and the flow of air exhaled from the lungs.
The inventions disclosed and taught herein are directed to a device and method for reducing or preventing snoring that is not present in the prior art. The inventions disclosed and taught herein are simple and comfortable to use, inexpensive to manufacture, and do not require surgical intervention.

Method and apparatus for mandibular support


The subject matter of this invention is a heat distribution management device in a treatment device of yarns in movement on a means of transport, said means of transport being able to be traversed by a flow of heat at or through the of orifices, characterized in that the device comprises at least one means of sealing by coverage of at least one part of the orifices of the means of transport, said means of sealing being independent of the means of transport.

At present, the treatment of a yarn or of a yarn bundle in a treatment device takes place through the placement of the yarn on the conveyor belt which moves inside the treatment device.
On the inside of the treatment device, the yarn or yarn bundle may be guided to switch means of transport passing from one belt to another depending on the defined path.
In the framework of heat treating, for example, by distribution of steam flows in a treatment chamber, the means of transport are realized in the form of a structure or transport device which allows a traversing by steam flows and/or by heat flows. This construction of the means of transport thereby participates in the heat treatment on each of the faces of the yarn bundle placed on the means of transport. Thus, the heat treatment is not exclusively accomplished on the sole exposed face of the yarn on the means of transport, which is to say to the detriment of the yarn face which would be in direct contact with the means of transport.
Nonetheless, this particular structure of the means of transport presents a disadvantage in the treatment of the ends of the yarn or of the yarn bundle.
Indeed, during the placement of the downstream yarn end, the surface of the means of transport is free on at least one part of its length up until the yarn or yarn bundle is placed on the whole of the length of the means of transport. Furthermore, when only a part of the length of the means of transport is covered by the yarn or yarn bundle, the part of the free means of transport then presents a structure which more readily enables the flows of heat and steam than the part of the means of transport which is covered by the yarn or yarn bundle. The flows of heat or of steam then have the tendency to firstly travel through the part of the means of transport which presents a free structure. Such a priority of placement is made to the detriment of the part of the means of transport which carries the yarn or yarn bundle and therefore to the detriment of the quality of the heat treatment of the yarns.
There is the identical problem at the upstream end of the treated yarn or yarn bundle. This problem of heat distribution in the heat treatment device therefore leads to the production of a yarn or yarn bundle having a heterogeneous quality of treatment over its whole length.

Heat distribution management device for yarn treatment


A method for managing multipath signals to be demodulated by a receiver with multiple demodulators. The method includes a series of steps, including receiving the multipath signals at a wireless communication receiver device, finding the multipath signals having sufficient signal strength for demodulation, and measuring an arrival time of one of the multipath signals. In one embodiment, the present invention also recites measuring a signal-to-noise ratio (SNR) level of one of the multipath signals, updating a multipath list with the arrival time and the signal-to-noise ratio if the multipath signal is identified based upon the arrival time with one of the multipath signals existing in the multipath list, and identifying newly-found multipath signals and evaluating one of the newly-found multipath signals based on the signal-to-noise ratio for categorization into one of a plurality of states. Additionally, in one embodiment of the present invention, the present method includes evaluating one of the existing multipath signals based on the signal-to-noise ratio for moving the multipath signal from one to another of a plurality of states, selectively providing one of the multipath signals for a demodulation operation based upon its state, selectively rejecting one of the multipath signals from the multipath list based on the signal-to-noise ratio, and repeating several of the above mentioned operations to process all found multipath signals.

The present claimed invention relates to the field of digital communication. Specifically, the present claimed invention relates to an apparatus and a method for managing multipath signals to be demodulated by a receiver with multiple demodulators.
Wireless telephony, e.g. mobile phone use, is a widely-used mode of communication today. Variable rate communication systems, such as Code Division Multiple Access (CDMA) spread spectrum systems, are among the most commonly deployed wireless technologies. Because of increasing demand and limited resources, a need arises to improve their capacity, fidelity, and performance.
Referring to prior art FIG. 1A, an illustration of multipath signal propagation between a conventional base station and a mobile phone is shown. A conventional base station 104 transmits a signal to a mobile station, e.g., phone, 102. Typically, the signal contains pilot information, that identifies the base station, and data information, such as voice content. A signal that can be transmitted directly to mobile phone 102 without interference, such as first signal 106a, provides the strongest signal. However, given the power limitations at which base station 104 can transmit the signal, and given the noise a signal may pick up, a need arises to improve the power and the SNR of the signal received at mobile phone.
Conventional methods will combine the portions of the transmitted signal that travel different paths to mobile unit 102. The multiple paths arise because of natural and man-made obstructions, such as building 108, hill 110, and surface 112, that deflect the original signal. Because of the paths over which these other signals travel, a time delay and performance deterioration intrinsically arises in the synchronization-sensitive and noise-sensitive data transmitted from base station 104 to mobile phone 102. However, to provide the strongest possible signal to a mobile phone, two or more of the signals from these multiple paths, e.g. path 106a-106d, may be combined. However, to efficiently combine and demodulate multipath signals, a need arises for a method to select the most worthwhile candidates from all the different multipaths received in mobile phone.
Corruption of a transmitted signal falls into two general categories: slowly-varying channel impairment and fast fading variation. Slowly-varying channel impairment arises from factors such as log-normal fading, or shadowing caused by movement or blocking as exemplified in prior art FIG. 1A, or slow fading. Slower variations, e.g., sub Hz, determine in effect, the xe2x80x9cavailabilityxe2x80x9d of the channel. In contrast, only the fast fading variation affects the details of the received waveform structure and the interrelationships of errors within a message. Hence, a need arises for a method that effectively choose the properties of the signal that influence its condition for demodulation.
Referring now to prior art FIG. 1B, a graph of two conventional multipath signal strengths over time is shown. Graph 100b has an abscissa 122 of time and an ordinate of signal-to-noise ratio (SNR) 120, e.g. pilot Ec/Io ratio. Third multipath signal 106c and fourth multipath signal 106d are shown as exemplary multipath signals received at mobile phone 102. Conventional methods typically select for combining, the multipath signals with the highest SNR. Thus, at time span A 124a, the dark line representing fourth multipath signal 106d has a higher SNR level than third multipath signal 106c, assuming both signals have the same noise level. However, at time span B 124b, the dashed line representing third multipath signal 106c has a higher SNR level. Given the closeness of the SNR, or of the signal to noise ratio, of these two multipath signals, the choice as to which signal will be chosen for the demodulator can oscillate back and forth.
This oscillation is a condition known as xe2x80x9cthrashing.xe2x80x9d The drawback with thrashing is that it consumes a significant amount of system resources, such as processor operations. During thrashing, the processor can be overloaded with operations that constantly assign and deassign the multiple demodulators to different multipath signals. Furthermore, thrashing may degrade the quality of the mobile phone 102 output signal, as the switching may cause a loss of data or an audible interference or it may introduce latency effects. Consequently, a need arises for a method to select the best multipath signal for combining while avoiding the effect of thrashing.
In summary, an apparatus and a method are needed to improve the capacity, fidelity, and performance of digital communication. More specifically, a need arises for a method to improve the power and the SNR of the signal received at mobile phone. In particular, a need arises for a method to select the most worthwhile candidates from all the different multipaths received in mobile phone for a subsequent demodulation and combining operation. Additionally, a need arises for a method to select the best multipath signal for combining while avoiding the effect of thrashing.
The present invention provides a method and apparatus for improving the capacity, fidelity, and performance of digital communication. More specifically, the present invention provides a method that improves the power and the SNR of the signal received at mobile phone. Beneficially, the present invention provides a method to select the most worthwhile candidates from all the different multipaths received in mobile phone for a subsequent demodulation and combining operation. Additionally, the present invention implements this method without the detrimental effects of thrashing.
In one embodiment, the present invention recites a method comprising several steps. In the first step the multipath signals are received at a wireless communication device. Next, multipath signals are searched by a searcher portion of the wireless communication device. The multipath signals having sufficient signal strength for demodulation are required. Then the SNR level and the arrival time are determined for the one multipath signal acquired. The wireless communication device stores the information about an arrival time, an SNR level, and a transmitting base station of each multipath signal found previously in a multipath list wherein the multipath signals are categorized into a plurality of states. Once the arrival time and the SNR level of the acquired multipath are determined, the multipath list is updated with the arrival time and the signal-to-noise ratio if the acquired multipath signal is identified based upon the arrival time with one of the multipath signals existing in the multipath list. Subsequently, if the acquired multipath signal does not match any one of the multipath signals existing in the multipath list based upon the arrival time, the acquired multipath signal is considered to be newly-found and the newly-found multipath signal is categorized into one of a plurality of states based upon the signal-to-noise ratio. The multipath signals in the multipath list are moved from one to another of multiple possible states based upon search measurement results. Finally, the one multipath signal acquired is evaluated for a demodulation operation based upon its state.
These states in which an acquired multipath signal may be categorized include a temporary state, a potential state, and an assigned state. The temporary state is a state to which low quality signals are categorized, a potential state is a state to which medium quality signals are categorized, and an assigned state is a state to which high quality signals are assigned. The quality of the signal is defined in terms of whether they meet certain performance thresholds. The thresholds include both a power, or SNR, level, and/or a temporal threshold, e.g. period of time over which the power, or SNR, level is maintained. That is, signals categorized in the assigned state are chosen first for demodulation because they are the highest quality signal. If no signals are categorized in the assigned state, a queue of potential signals may be available for immediate assignment to a demodulator for demodulation, thus avoiding latency problems of the prior art. By using this practice, the present invention provides a queue of potential signals that are categorized in states according to historical performance. Thus the present invention overcomes the thrashing drawbacks of the prior art signal selection by using a state environment in which to categorize the multipath signals.
In another embodiment, the present invention recites a communication device having a transceiver, a searcher, a receiver, a processor and a computer readable memory, all coupled together. The memory portion of the communication device contains program instructions that, when executed via the processor, implement the aforementioned method for managing demodulators for multipath signals in a communication device.
These and other objects and advantages of the present invention will become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the various drawing figures.

Method and apparatus for managing multipath signals for a receiver with multiple demodulators