A method and an apparatus for storage and transport of drilling waste is provided. A number of storage containers (12) are anchored to the sea bed by means of anchors (15) and cables (13). The location of the containers (12) is marked with buoys (17). The containers (12) are of adjustable buoyancy, and are arranged to remain below the surface of the sea. Drilling waste is macerated on board a drilling vessel (18), and pumped via conduits (20) into the containers (12). Once the containers (12) are full, a tug (22) collects the containers (12) and transports them to an onshore waste recycling facility, while empty tanks are returned to the drilling vessel (18) to be reused. The containers (12) may be arranged to agitate stored waste, either by means of an internal agitator, or by virtue of fins or paddles mounted on the containers (12), to rotate the containers in response to sea currents.

The present invention relates to a method and an apparatus for storage and transport of drilling waste, such as drill cuttings and similar substances as produced in the course of marine drilling operations.
In drilling operations, particularly in the drilling of oil and gas wells, drilling mud is often pumped downhole for a number of different purposes, such as lubrication of the drill string, prevention of corrosion, and transport of drill cuttings uphole.
Drilling muds may be oil or water-based, although oil-based muds are preferred in lower sections of bore, and are also generally less costly than water-based muds.
Once the drilling mud is returned to the surface, it is passed through screens or other filtering arrangements to separate the drill cuttings from the mud. The drill cuttings are collected and, in offshore operations, stored on the drilling platform or vessel before being transported onshore for processing. Once onshore, oil and moisture are separated from the cuttings, the cuttings then being sent for landfill while the oil is recycled. Alternatively, the cuttings may be utilised as road building material or as fertiliser filler. It was formerly the practice to dump the cuttings at sea; however the presence of contaminants in the cuttings creates environmental problems. Further, in many jurisdictions there is legislation pending or in place which now only permits xe2x80x9czero dischargexe2x80x9d drilling operations; that is, dumping of untreated cuttings is prohibited.
Prior to being transported onshore for processing, drilling waste is presently stored in skips or other containers, of typically 5 tonnes capacity, on deck of the drilling platform or vessel. As a typical drilling operation may produce up to 800 tonnes of drilling waste, many such containers will be necessary. Not only does this take up valuable deck space, but if, for example, inclement weather should prevent transport vessels from removing filled containers from a drilling platform, drilling operations may have to be suspended for a period until the containers are removed.
Furthermore, the loading of skips or containers onto a transport vessel must typically be done by crane, one skip at a time. This is a slow process, and requires many crane movements, thereby increasing the risk of accidents occurring.
An alternative approach is to macerate drill cuttings and store them on or below the deck of the drilling platform or vessel. The macerated cuttings are subsequently pumped onto a transport vessel. However, such macerated cuttings are generally too fine to be handled easily in conventional cuttings processing facilities; and while being stored on the platform must be maintained in circulation, to avoid settling out of the cuttings, which would prevent pumping onto a transport vessel.
Furthermore, all of these known approaches are heavily dependent on weather conditions being suitable to permit transport vessels to approach the offshore facility and to permit transfer of materials or containers between the vessel and the facility.
In some areas, for example, the eastern Atlantic Ocean to the west of the Shetland Isles, it has been estimated that in winter some 65-70% of drilling costs are weather related. Reduction of the reliance on favourable weather conditions would therefore be of considerable benefit.
It is among the objects of embodiments of the present invention to obviate or alleviate these and other disadvantages of the prior art. In particular, in the present invention, the storage of drilling waste is not dependent on deck area of the drilling platform; and the method is far less susceptible to adverse weather conditions than the prior art.
According to a first aspect of the present invention, there is provided a method of storing and transporting drilling waste produced in an offshore drilling operation, the method comprising the steps of:
providing a movable container for receiving drilling waste;
securing the container in a position below sea-level;
connecting the container to a drilling platform or vessel; and
conveying drilling waste from the platform or vessel to the container.
The present invention does not require the container to be located on the drilling platform or vessel, so releasing the method from many of the constraints of the prior art. In particular, the storage of drilling waste is not dependent on using deck area of the drilling platform; and the method is less susceptible to adverse weather conditions than the prior art.
In a preferred embodiment, at least two containers are provided. Preferably, the containers are together of a volume sufficient to contain the drilling waste from a complete drilling operation. Most preferably, each container is capable of holding at least 500 tonnes of drilling waste.
Preferably, the method further comprises the step of agitating the drilling waste within the container. Conveniently this may be, achieved by rotating or otherwise moving the container in the water; or by providing an agitator within the container. The container may be provided with external fins or the like which tend to rotate or move the container in response to sea currents. This movement prevents waste from settling, and possibly unbalancing the container; settled waste may also be more difficult to remove from the container.
Preferably, the method further comprises the steps of:
releasing the container from its position; and
transporting the container to a drilling waste processing facility.
The released container may have its buoyancy increased, such that the container rises in the water to a position at or closer to the sea surface.
As the container is remains in the water, transportation of the container requires few if any lifting or crane operations. Again, this reduces the vulnerability to adverse weather conditions of the transport process.
Preferably the container is positioned spaced from the platform or vessel. This facilitates installation of the container, as the tug, work boat or other vessel utilised to transport the container may be manoeuvred with less risk of coming into contact with the platform or vessel, and facilitates installation of the container in adverse weather conditions.
Preferably, the container is secured in position by an anchoring means attached to the seabed. Conveniently, the anchoring means may be one or more anchors, which may be conventional anchors or suction anchors, or may be a base sitting on or anchored to the sea bed and configured so as to receive a container. Alternatively, or in addition, the container may be of adjustable buoyancy, and may be ballasted to remain at a predetermined depth in the sea. Most preferably, the container is secured such that it lies between 50 to 150 feet beneath the sea surface, and is thus relatively unaffected by weather conditions. Of course in shallow water, or in situations where weather conditions are relatively benevolent, the container may be maintained at a lesser depth, and even may have portions extending above the surface.
Preferably, the container is connected to the drilling platform or vessel by means of a conduit, and preferably by means of a dual conduit. Preferably, the conduit is a flexible hose. Most preferably, a plurality of flexible hoses are provided. The flexible hoses will be constructed to withstand anticipated weather conditions, while provision of a plurality of hoses provides for redundancy, so that drilling operations may continue if one of the hoses is temporarily blocked, disconnected or damaged.
Preferably, the method further comprises the step of conveying drilling waste, from the platform to a smaller volume holding tank on the platform prior to conveying the waste to the container. This additional step facilitates pre-storage processing of the drilling waste prior to storage. Alternatively, the drilling waste may be transported directly to the container.
Preferably, the method further comprises the step of macerating the drilling waste prior to conveying the waste to the container. This ensures that the solids in the waste are of a substantially uniform size, so facilitating conveyance to the container, and a reduced risk of blockage. However, the degree of maceration is preferably selected such that the resulting slurry is of sufficient viscosity to facilitate subsequent handling and processing.
Preferably, the method further comprises the step of determining the liquid, water or oil content and then adjusting the liquid or oil content to facilitate handling and maintaining solids in suspension. Thus, for particularly xe2x80x9cwetxe2x80x9d waste it may be desirable to extract oil is from the waste prior to conveying the waste to the container, however this is unlikely to be commonplace. This would enables at least some of the oil to be recycled and reused without the need to transport the waste onshore, and also reduces the volume of waste it is necessary to store. More likely, the method will further comprise the step of adding oil to the drilling waste prior to conveying the waste to the container; the oil may be used or recycled drilling fluid. This has the effect of xe2x80x9cslurrifyingxe2x80x9d relatively dry waste, which generally makes the waste easier to convey to the container and easier to process once onshore.
Preferably, the method further comprises the step of agitating the contents of the container whilst it is being transported to the recycling facility. This prevents the waste from settling out, which increases the difficulty of recycling.
Preferably, the method further comprises the steps of:
providing an additional container; and
maintaining at least one container at the platform or vessel.
This enables drilling waste to be received on a continuous basis, so reducing the likelihood that drilling operations will have to be suspended due to lack of storage. In the preferred embodiment, two containers are maintained at the platform or vessel during each drilling operation.
According to a second aspect of the present invention, there is provided an apparatus for use in storage and transport of drilling waste, the apparatus comprising movable containment means for containing drilling waste; securing means for releasably securing the container in a position below sea level; and connection means for connecting the container to a drilling platform or vessel.
Preferably, the containment means comprises a container or other closed vessel. The container may be of reinforced concrete construction or a steel fabrication; preferably the container is fabricated of steel in a double skin construction. Any suitable material may however be used, including flexible fabrics or other materials.
Preferably, the container is capable of holding at least 500 tonnes of drilling waste.
Preferably, the securing means comprises an anchor means for attaching the container to the sea bed. The anchor means may comprise a base to be located on the seabed, configured so as to receive and retain at least one container; alternatively or in addition the anchor means may comprise one or more anchors for attachment to the container and the sea floor.
Preferably, the container comprises agitation means, to enable the contents of the container to be agitated. The agitation means may comprise an internal rotating paddle; or may comprise external fins mounted on the container, such that the container rotates in response to sea currents.
Preferably, the container is of adjustable buoyancy; as the container is filled with drilling waste, the buoyancy may be adjusted to maintain the container at a substantially constant level in the water. Preferably, the container comprises a double skin, with a cavity between the skins which may be filled with air or seawater as desired, in order to adjust buoyancy.
Preferably, the connection means comprises a flexible conduit for conveying drilling waste, and most preferably a plurality of flexible conduits.
Preferably, the apparatus further comprises a holding tank for holding drilling waste prior to conveying the waste to the container. Preferably, the holding tank includes a macerator. The holding tank may include a press for extracting oil or water from the drilling waste, but is more likely to include means for adding liquid, and in particular oil, to the drilling waste.


Disclosed is a system for delivering an oral care substance to the oral cavity comprising: (a) a delivery composition comprised of: (i) an organosiloxane resin; (ii) a volatile carrier capable of solubilizing the organosiloxane resin; (iii) a rheology modifier; and (iv) at least one oral care substance; and (b) a protective composition comprised of: (i) an organosiloxane resin; and (ii) a volatile carrier capable of solubilizing the organosiloxane resin. Further disclosed is a system for delivering an oral care substance to the oral cavity comprising: (a) a delivery composition comprised of: (i) an organosiloxane resin; (ii) a fluid diorganopolysiloxane-based polymer; (iii) a volatile carrier capable of solubilizing the organosiloxane resin and the fluid diorganopolysiloxane-based polymer; (iv) a rheology modifier; and (v) at least one oral care substance; and (b) a protective composition comprised of: (i) an organosiloxane resin; and (ii) a volatile carrier capable of solubilizing the organosiloxane resin. The protective composition may further comprise a fluid diorganopolysiloxane-based polymer and/or a rheology modifier. Still further disclosed is a method of using these systems.

The present invention relates to systems for delivering oral care substances to the surfaces of the teeth and for prolonging such delivery. More specifically, the present invention relates to a system comprising a delivery composition comprising organosiloxane resins and at least one oral care substance for delivering the oral care substance, and a protective composition comprised of organosiloxane resins for prolonging the presence of the delivery composition in the oral cavity. The delivery composition forms a film on the surface to which it has been applied and provides sustained release of the oral care substance from the film for prolonged therapeutic, prophylactic, and/or cosmetic benefits. In addition, it is believed that the systems herein may further provide sustained release benefits to other oral surfaces, such as the gingival and mucosal tissues, as well as to the surfaces of the teeth.
Oral care products by which various oral care substances or actives can be delivered to the soft and hard tissues of the oral cavity have previously been known. Examples of such oral care products include, for example, brushing aids such as dentifrice products for delivery of anti-caries actives such as fluoride or other actives for the reduction of the bacteria that lead to the formation of plaque, and mouthwashes containing breath freshening actives and/or anti-bacterial actives. In addition, bleaching agents such as peroxide that can be applied directly to the surfaces of the teeth, i.e., to the tooth enamel, have been developed.
However, it has been found that such conventional product forms typically do not provide substantivity sufficient to maintain actives on the hard and soft oral tissues for a period of time sufficient to enhance or prolong the therapeutic, prophylactic, and/or cosmetic benefits provided by the actives. Neither have such conventional product forms been able to provide sustained delivery of oral care actives, without periodic reapplication at relatively short time intervals, or without a special delivery device or containment means such as a mouthpiece.
Attempts have previously been made to enhance the substantivity of whitening bleaches, bactericides, and other active components of oral care products. See, e.g., U.S. Pat. No. 5,425,953 to Sintov et al. on Jun. 20, 1995, in which a film forming, water-soluble cellulosic polymer is used to deliver a bleaching agent to the teeth; U.S. Pat. No. 5,438,076 to Friedman et al., in which liquid methacrylate acid copolymer compositions are used to deliver a bacteriocidal pharmacological agent; and International Patent Appln. No. PCT/CN97/00 to Huang, published on Jul. 24, 1997, disclosing a film-coating composition comprising cellulose and polyvinyl acetal, coumarone-indene resin, or shellac as a film former to deliver bleaches to the tooth enamel.
However, the above systems are water-soluble, i.e., they are readily dissolved by saliva, generally within about 1-3 hours after application. Therefore, their degree of durability is low, and they cannot provide long-term delivery of the active ingredient that is present in the composition. In addition, their water-soluble nature precludes them from being used with oral care actives that would be unstable in water-based films. Sodium percarbonate is one example of such an active; it would be unstable in the high pH environment of an aqueous-based film.
In order to provide an applied composition with a relatively higher degree of durability, the use of protective coatings that are applied to the teeth has been described. See, U.S. Pat. No. 5,401,528, to Schmidt on Mar. 18, 1995, in which organically modified silicic acid polycondensates are deposited on the teeth, then polymerized in-situ by curing, to coat the teeth in order to protect them from plaque deposits. This system is not a true delivery system by which an active ingredient is released over time; instead, it provides a barrier by which the deleterious effect of plaque-causing bacteria may be diminished.
Although such a barrier coating may offer a benefit in terms of enhanced durability, it requires the use of special equipment and complex application; thus, it cannot be performed at home and cannot be used for self-treatment.
Therefore, it can be seen that none of these previous developments can offer the combination of both long-term delivery of an oral care substance or active ingredient and the convenience of discrete self-treatment and home use. Based on the foregoing, there is a need for a convenient delivery system for various oral care substances in which the substantivity of the active ingredients is enhanced, and in which the presence of the oral care substance in the oral cavity is prolonged to further enhance the therapeutic, prophylactic, and/or cosmetic benefits provided by the actives. None of the existing art provides all of the advantages and benefits of the present invention.
The present invention is directed to systems for delivering an oral care substance to the oral cavity comprising: (a) a delivery composition comprised of: (i) an organosiloxane resin; (ii) a volatile carrier capable of solubilizing the organosiloxane resin; (iii) a rheology modifier; and (iv) at least one oral care substance; and (b) a protective composition comprised of: (i) an organosiloxane resin; and (ii) a volatile carrier capable of solubilizing the organosiloxane resin. The protective composition may further comprise a fluid diorganopolysiloxane-based polymer and/or a rheology modifier.
The present invention is further directed to systems for delivering an oral care substance to the oral cavity comprising: (a) a delivery composition comprised of: (i) an organosiloxane resin; (ii) a fluid diorganopolysiloxane-based polymer; (iii) a volatile carrier capable of solubilizing the organosiloxane resin and the fluid diorganopolysiloxane-based polymer; (iv) a rheology modifier; and (v) at least one oral care substance; and (b) a protective composition comprised of: (i) an organosiloxane resin; and (ii) a volatile carrier capable of solubilizing the organosiloxane resin. The protective composition may further comprise a fluid diorganopolysiloxane-based polymer and/or a rheology modifier.
The present invention further is directed to a method of using these systems.
These and other features, aspects, and advantages of the invention will become evident to those skilled in the art from a reading of the present disclosure.
While the specification concludes with claims particularly pointing out and distinctly claiming the invention, it is believed that the present invention will be better understood from the following description.
All percentages and ratios used hereinafter are by weight of total composition, unless otherwise indicated.
All measurements referred to herein are made at 25xc2x0 C. unless otherwise specified.
All percentages, ratios, and levels of ingredients referred to herein are based on the actual amount of the ingredient, and do not include solvents, fillers, or other materials with which the ingredient may be combined as a commercially available product, unless otherwise indicated.
All publications, patent applications, and issued patents mentioned herein are hereby incorporated in their entirety by reference. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention.
Herein, xe2x80x9ccomprisingxe2x80x9d means that other steps and other components which do not affect the end result can be added. This term encompasses the terms xe2x80x9cconsisting ofxe2x80x9d and xe2x80x9cconsisting essentially of.xe2x80x9d
The delivery systems herein are comprised of a delivery composition and a protective composition. The delivery and protective compositions herein comprise essential components, as well as optional components. The essential and optional components of these compositions of the present invention are described in the following paragraphs.
Delivery Composition
The delivery composition herein is a composition for delivering an oral care substance to the oral cavity. The delivery composition comprises an oral care substance for providing a therapeutic, prophylactic, and/or cosmetic benefit to the oral cavity. One preferred embodiment of the delivery composition is comprised of an organosiloxane resin; a volatile carrier capable of solubilizing the organosiloxane resin; a rheology modifier; and at least one oral care substance.
Another preferred embodiment of the delivery composition is comprised of an organosiloxane resin; a fluid diorganopolysiloxane-based polymer; a volatile carrier capable of solubilizing the organosiloxane resin and the fluid diorganopolysiloxane-based polymer; a rheology modifier; and at least one oral care substance.
Protective Composition
The protective composition acts as a protective coating to prolong the presence of the oral care substance or substances contained in the delivery composition in the oral cavity. The protective composition need not comprise an oral care substance.
One preferred embodiment of the protective composition is comprised of an organosiloxane resin and a volatile carrier capable of solubilizing the organosiloxane resin. A rheology modifier may also be present.
Another preferred embodiment of the protective composition is comprised of an organosiloxane resin, a fluid diorganopolysiloxane-based polymer, a volatile carrier capable of solubilizing the organosiloxane resin and the fluid diorganopolysiloxane-based polymer. A rheology modifier may also be present.
The protective composition need not comprise an oral care substance in order to act as a protective coating for the delivery composition. However, it should be noted that any of the oral care substances described herein could additionally be added to the protective composition.
It should also be noted that more than one application of the protective composition, following the application of the delivery composition, can be made. Multiple applications of the protective composition can be made and are within the scope of the present invention.
Organosiloxane Resins
Silicone resins are highly crosslinked polymeric siloxane systems. The crosslinking is introduced through the incorporation of tri-functional and tetra-functional silanes with mono-functional or di-functional, or both, silanes during manufacture of the silicone resin. As is well understood in the art, the degree of crosslinking that is required in order to result in a silicone resin will vary according to the specific silane units incorporated into the silicone resin. In general, silicone materials which have a sufficient level of trifunctional and tetrafunctional siloxane monomer units, and hence, a sufficient level of crosslinking, such that they dry down to a rigid, or hard, film are considered to be silicone resins. The ratio of oxygen atoms to silicon atoms is indicative of the level of crosslinking in a particular silicone material. Silicone materials which have at least about 1.1 oxygen atoms per silicon atom will generally be silicone resins herein. Preferably, the ratio of oxygen:silicon atoms is at least about 1.2:1.0.
Silicone materials and silicone resins in particular can conveniently be identified according to a shorthand nomenclature system well known to those skilled in the art as the xe2x80x9cMDTQxe2x80x9d nomenclature. Under this system, the silicone is described according to the presence of various siloxane monomer units which make up the silicone. Briefly, the symbol M denotes the mono-functional unit (CH3)3SiO)0.5; D denotes the difunctional unit (CH3)2SiO; T denotes the trifunctional unit (CH3)SiO1.5; and Q denotes the quadra- or tetra-functional unit SiO2. Note that a small amount, up to about 5% of silanol or alkoxy functionality may also be present in the resin structure as a result of processing.
Primes of the unit symbols, e.g., Mxe2x80x2, Dxe2x80x2, Txe2x80x2, and Qxe2x80x2, denote substituents other than methyl, and must be specifically defined for each occurrence. Typical alternate substituents include groups such as vinyl, phenyl, amino, hydroxyl, etc. The molar ratios of the various units, either in terms of subscripts to the symbols indicating the total number of each type of unit in the silicone, or an average thereof, or as specifically indicated ratios in combination with molecular weight, complete the description of the silicone material under the MDTQ system. Higher relative molar amounts of T, Q, Txe2x80x2 and/or Qxe2x80x2 to D, Dxe2x80x2, M and/or Mxe2x80x2 in a silicone resin is indicative of higher levels of crosslinking. As discussed before, however, the overall level of crosslinking can also be indicated by the oxygen to silicon ratio.
The organosiloxane resins are solid at about 25xc2x0 C. and the average molecular weight of the resins is from about 1,000 to about 10,000. The resins are soluble in organic solvents such as toluene, xylene, isoparaffins, and cyclosiloxanes or the volatile carrier described below, indicating that the resin is not sufficiently crosslinked such that the resin is insoluble in the volatile carrier.
The silicone resins preferred for use herein are MQ, MT, MTQ, and MDTQ resins; such MQ resins are disclosed in U.S. Pat. No. 5,330,747, Krzysik, issued Jul. 19, 1994. Thus, the preferred silicone substituent is methyl. Especially preferred are MQ resins wherein the M:Q ratio is from about 0.5:1.0 to about 1.5:1.0. Organosiloxane resins such as these are commercially available, for example, Wacker 803 and 804 available from Wacker Silicones Corporation of Adrian, Mich., US, and G.E. 1170-002 from the General Electric Company.
The level of the resin that is used in the compositions is dependent on its degree of solubility in the formulation, particularly in the solvents used. Generally, the range of resin used in the present invention is from about 5% to about 70%, preferably from about 15% to about 45%, and even more preferably from about 20% to about 40%.
Fluid Diorganopolysiloxane-based Polymers
In addition to the organosiloxane resins disclosed above, the compositions of the present invention may further comprise a fluid diorganopolysiloxane-based polymer to be combined with the organosiloxane resins. Said fluid diorganopolysiloxane-based polymers useful in the present invention span a large range of viscosities; from about 10 to about 10,000,000 centistokes (cSt) at 25xc2x0 C. Some diorganopolysiloxane polymers useful in this invention exhibit viscosities greater than 10,000,000 centistokes (cSt) at 25xc2x0 C. and therefore are characterized by manufacturer specific penetration testing. Examples of this characterization are GE silicone materials SE 30 and SE 63 with penetration specifications of 500-1500 and 250-600 (tenths of a millimeter) respectively.
Among the fluid diorganopolysiloxane-based polymers of the present invention are diorganopolysiloxane polymers comprising repeating units, where said units correspond to the formula (R2SiO)n, where R is a monovalent hydrocarbon radical containing from 1 to 6 carbon atoms, preferably selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, hexyl, vinyl, allyl, cyclohexyl, amino alkyl, phenyl, fluoroalkyl and mixtures thereof. The fluid diorganopolysiloxane polymers employed in the present invention may contain one or more of these hydrocarbon radicals as substituents on the siloxane polymer backbone. The fluid diorganopolysiloxane polymers may be terminated by triorganosilyl groups of the formula (Rxe2x80x23Si) where Rxe2x80x2 is a radical selected from the group consisting of monovalent hydrocarbons containing from 1-6 carbon atoms, hydroxyl groups, alkoxyl groups and mixtures thereof. The fluid diorganopolysiloxane polymer must be compatible in solution with the organosiloxane resin and the volatile carrier. The term xe2x80x9ccompatiblexe2x80x9d refers to the formation of a single phase solution when the fluid diorganopolysiloxane polymer, the organosiloxane resin and the volatile carrier are mixed together in ratios required for a specific formulation. For example, the lower viscosity fluid diorganopolysiloxane polymers (viscosity of about 10 to 100 cSt.) are particularly useful when using ethanol as the principal volatile carrier. For higher viscosity polymers, e.g., poly(dimethylsiloxane), herein referred to as PDMS or silicone gum, having a viscosity of at least 100,000 cSt, volatile carriers other than ethanol are preferred.
Silicone gum corresponds to the formula:
where R is a methyl group.
Fluid diorganopolysiloxane polymers such as these are commercially available, for example, SE 30 silicone gum and SF96 silicone fluid available from the General Electric Company. Similar materials can also be obtained from Dow Corning and from Wacker Silicones.
Another fluid diorganosiloxane-based polymer preferred for use in the present invention is a dimethicone copolyol to modify film forming characteristics as desired. The dimethicone copolyol can be further characterized as polyalkylene oxide modified polydimethysiloxanes, such as manufactured by the Witco Corporation under the trade name Silwet. Similar materials can be obtained from Dow Corning, Wacker Silicones and Goldschmidt Chemical Corporation as well as other silicone manufacturers.
In preferred embodiments of the present invention, the ratio of organosiloxane resin to fluid diorganopolysiloxane-based polymer is preferably from about 15:1 to about 1:15, more preferably from about 2:1 to about 8:1, and still more preferably from about 4:1 to about 6:1.
Volatile Carriers
In the present invention, the organosiloxane resin and the fluid diorganosiloxane-based polymer above must be easily transferred to the oral cavity surfaces, such as to the tooth enamel. To achieve delivery, it is necessary that the resin or the resin/polymer combination above be incorporated into a carrier, specifically a volatile carrier which must quickly volatilize from the oral cavity surfaces, leaving a film on the application surfaces. The volatile carrier must solubilize the organosiloxane resin and if present in the composition, the fluid diorganosiloxane-based polymer.
The volatile carrier comprises from about 10% to about 90%, preferably from about 15% to about 80%, and more preferably from about 20% to about 70% of the composition. The volatile carrier of the present invention is selected from the group consisting of hydrocarbon oils, volatile silicones, non-hydrocarbon solvents, and mixtures thereof.
Hydrocarbon oils useful in the present invention include those having boiling points in the range of 60-260xc2x0 C., more preferably hydrocarbon oils having from about C8 to about C20 chain lengths, most preferably C8 to C20 isoparaffins. Of these isoparaffins most preferred are selected from the group consisting of isododecane, isohexadecane, isoeocosane, 2,2,4-trimethylpentane, 2,3-dimethylhexane and mixtures thereof. Most preferred is isododecane, available as, for example, Permethyl 99A from Permethyl Corporation corresponding to the formula:
CH3(CH2)10CH3
Preferred volatile silicone fluids include cyclomethicones having 3, 4 and 5 membered ring structures corresponding to the formula:
where X is from about 3 to about 6. Such volatile silicones include 244 Fluid, 344 Fluid and 245 Fluid, and 345 Fluid all from Dow Corning Corporation.
The general classes of non-hydrocarbon solvents useful herein include esters, ketones, alcohols, fluorocarbons and fluorocarbon ethers having boiling points in the range of 60 to 200xc2x0 C. Non-hydrocarbon solvents or mixtures thereof particularly useful include those that are capable of solubilizing the resin and/or the diorganopolysiloxane-based polymer. Such solvents include but are not limited to ethanol, acetone, butanone, ethyl acetate, propyl acetate, amyl acetate, ethyl butyrate, methyl nonafluoroisobutyl ether, methyl nonafluorobutyl ether, and mixtures thereof. These non-hydrocarbon solvents are readily available such as ethyl acetate and methyl ethyl ketone, both supplied by J. T. Baker of Phillispburg, N.J., and HFE (a mixture of methyl nonafluoroisobutyl ether and methyl nonafluorobutyl ether), supplied by the 3M Company.
Rheology Modifiers
The compositions further comprise a rheology modifier which inhibits settling and separation of components or controls settling in a manner which facilitates re-dispersion and may control rheological flow properties. Suitable rheology modifiers herein include organo modified clays, silicas, polyethylene, and mixtures thereof. The preferred organophilic clays comprise quaternium-18 hectorite or Stearalkonium hectorite, such as Bentone 27 and 38(trademark) from Rheox, organoclay dispersion such as Bentone ISD gel(trademark); or bentonite organo modified clays such as Bentone 34(trademark) from Rheox or the Claytone Series(trademark) from Southern Clay Products; and mixtures thereof. The preferred silicas may be fumed silica such as the Aerosil(trademark) series from Degussa or the Cab-o-sil(trademark) series from Cabot Corporation, silica gels such as the Sylodent(trademark) or Sylox(trademark) series from W. R. Grace and Co. or precipitated silica such as Zeothix 265 from J. M. Huber Corporation.
The rheology modifier is preferably present in the composition at a level of from about 0.1% to about 30%, preferably from about 0.5% to about 10%, and even more preferably about 1% to about 3% of the composition.
Oral Care Substances
The oral care substance preferably contains an active at a level where upon directed use, the benefit sought by the wearer is promoted without detriment to the oral surface to which it is applied. Examples of the oral conditions these actives address include, but, are not limited to, appearance and structural changes to teeth, whitening, stain bleaching, stain removal, plaque removal, tartar removal, cavity prevention and treatment, inflamed and/or bleeding gums, mucosal wounds, lesions, ulcers, aphthous ulcers, cold sores, tooth abscesses, and the elimination of mouth malodor resulting from the conditions above and other causes such as microbial proliferation.
Suitable oral care substances include any material that is generally considered safe for use in the oral cavity and that provides changes to the overall appearance and/or health of the oral cavity. The level of oral care substance in the compositions of the present invention is generally, unless specifically noted, from about 0.01% to about 50%, preferably from about 0.1% to about 20%, more preferably from about 0.5% to about 10%, and even more preferably from about 1% to about 7%, by weight of the composition.
Oral care compositions or substances of the present invention may include many of the actives previously disclosed in the art. The following is a non-limiting list of oral care actives that may be used in the present invention.
1. Teeth Whitening Actives
Teeth whitening actives may be included in the oral care substance of the present invention. The actives suitable for whitening are selected from the group consisting of the peroxides, metal chlorites, perborates, percarbonates, peroxyacids, persulfates, and combinations thereof. Suitable peroxide compounds include hydrogen peroxide, urea peroxide, calcium peroxide, carbamide peroxide, and mixtures thereof. Most preferred is carbamide peroxide. Suitable metal chlorites include calcium chlorite, barium chlorite, magnesium chlorite, lithium chlorite, sodium chlorite, and potassium chlorite. Additional whitening actives may be hypochlorite and chlorine dioxide. The preferred chlorite is sodium chlorite. A preferred percarbonate is sodium percarbonate. Preferred persulfates are xones.
2. Anti-tartar Agents
Anti-tartar agents known for use in dental care products include phosphates. Phosphates include pyrophosphates, polyphosphates, polyphosphonates and mixtures thereof. Pyrophosphates are among the best known for use in dental care products. Pyrophosphate and polyphosphate ions are delivered to the teeth derive from pyrophosphate polyphosphate salts. The pyrophosphate salts useful in the present compositions include the dialkali metal pyrophosphate salts, tetra-alkali metal pyrophosphate salts, and mixtures thereof. Disodium dihydrogen pyrophosphate (Na2H2P2O7), tetrasodium pyrophosphate (Na4P2O7), and tetrapotassium pyrophosphate (K4P2O7) in their unhydrated as well as hydrated forms are the preferred species. While any of the above mentioned pyrophosphate salts may be used, tetrasodium pyrophosphate salt is preferred. Sodium polyphosphate and triethanolamine polyphosphates, for example, are preferred.
The pyrophosphate salts are described in more detail in Kirk and Othmer, Encyclopedia of Chemical Technology, Third Edition, Volume 17, Wiley-Interscience Publishers (1982). Additional anticalculus agents include pyrophosphates or polyphosphates disclosed in U.S. Pat. No. 4,590,066 issued to Parran and Sakkab on May 20, 1986; 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 dated 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.
Agents that may be used in place of or in combination with the pyrophosphate salt include such known materials as synthetic anionic polymers including polyacrylates and copolymers of maleic anhydride or acid and methyl vinyl ether (e.g., Gantrez), as described, for example, in U.S. Pat. No. 4,627,977, to Gaffar et al.; as well as, e.g., polyamino propoane sulfonic acid (AMPS), zinc citrate trihydrate, polyphosphates (e.g., tripolyphosphate; hexametaphosphate), diphosphonates (e.g., EHDP; AHP), polypeptides (such as polyaspartic and polyglutamic acids), and mixtures thereof.
3. Fluoride Ion Source
Fluoride ion sources are well known for use in oral care compositions as anticaries agents. Fluoride ions are contained in a number of oral care compositions for this purpose, particularly toothpastes. Patents disclosing such toothpastes include U.S. Pat. No. 3,538,230, Nov. 3, 1970 to Pader et al; U.S. Pat. No. 3,689,637, Sep. 5, 1972 to Pader; U.S. Pat. No. 3,711,604, Jan. 16, 1973 to Colodney et al; U.S. Pat. No. 3,911,104, Oct. 7, 1975 to Harrison; U.S. Pat. No. 3,935,306, Jan. 27, 1976 to Roberts et al; and U.S. Pat. No. 4,040,858, Aug. 9, 1977 to Wason.
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 instant compositions. Examples of suitable fluoride ion-yielding materials are found in Briner et al; U.S. Pat. No. 3,535,421; issued Oct. 20, 1970 and Widder et al; U.S. Pat. No. 3,678,154; issued Jul. 18, 1972. Preferred fluoride ion sources for use herein include sodium fluoride, potassium fluoride and ammonium fluoride. Sodium fluoride is particularly preferred. Preferably the instant compositions provide from about 50 ppm to 10,000 ppm, more preferably from about 100 to 3000 ppm, of fluoride ions in the compositions that contact dental surfaces when used with the delivery system of the present invention.
4. Anti-microbial Agents
Anti-microbial 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 ed. (1989), pp. 1529 (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, Feb. 19, 1991, preferably magnesium monopotassium 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); octenidine; delmopinol, octapinol, and other piperidino derivatives; nicin preparations; zinc/stannous ion agents; antibiotics such as augmentin, amoxicillin, tetracycline, doxycycline, minocycline, and metronidazole; and analogs and salts of the above; essential oils including thymol, geraniol, carvacrol, citral, hinokitiol, eucalyptol, catechol (particularly 4-allyl catechol) and mixtures thereof; methyl salicylate; hydrogen peroxide; metal salts of chlorite and mixtures of all of the above.
5. Anti-inflammatory Agents
Anti-inflammatory 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, non-steroidal anti-inflammatory agents or NSAIDs such as ketorolac, flurbiprofen, ibuprofen, naproxen, indomethacin, aspirin, ketoprofen, piroxicam and meclofenamic acid. Use of NSAIDs such as Ketorolac are claimed in U.S. Pat. No. 5,626,838, issued May 6, 1997. Disclosed therein are methods of preventing and, or treating primary and reoccurring squamous cell carcinoma of the oral cavity or oropharynx by topical administration to the oral cavity or oropharynx an effective amount of an NSAID.
6. 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, and mixtures thereof.
Minerals that can be included with the compositions of the present invention include calcium, phosphorus, fluoride, zinc, manganese, potassium and mixtures thereof. These minerals are disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St. Louis, Mo., (copyright)1997, pp10-17.
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. Such vitamins are disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St. Louis, Mo., (copyright)1997, pp. 3-10.
Oral nutritional supplements include amino acids, lipotropics, fish oil, and mixtures thereof, as disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St. Louis, Mo., (copyright)1997, pp. 54-54e. Amino acids include, but, are not limited to L-Tryptophan, L-Lysine, Methionine, Threonine, Levocarnitine or L-carnitine and mixtures thereof. Lipotropics include, but, are not limited to choline, inositol, betaine, linoleic acid, linolenic acid, and mixtures thereof. Fish oil contains large amounts of Omega-3 (N-3) Polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid.
Entenal nutritional supplements include, but, are not limited to protein products, glucose polymers, corn oil, safflower oil, medium chain triglycerides as disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St. Louis, Mo., (copyright)1997, pp. 55-57.
7. Mouth and Throat Products
Other materials that can be used with the present invention include commonly known mouth and throat products. Such products are disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St. Louis, Mo., (copyright)1997, pp. 520b-527. These products include, but, are not limited to anti-fungal, antibiotic and analgesic agents.
8. Antioxidants
Antioxidants are generally recognized 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 Marcel Dekker, Inc. Antioxidants that may be included in the oral care composition or substance of the present invention include, but are not limited to Vitamin E, ascorbic acid, Uric acid, carotenoids, Vitamin A, flavonoids and polyphenols, herbal antioxidants, melatonin, aminoindoles, lipoic acids and mixtures thereof.
9. H-2 Antagonists
Histamine-2 (H-2 or H2) receptor antagonist compounds (H-2 antagonists) may be used in the oral care composition 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 or H1) receptors. Selective H-2 antagonists stimulates the contraction of smooth muscle from various organs, such as the gut and bronchi; this effect can be suppressed by low concentrations of mepyraminexe2x80x94a typical antihistaminic drug. The pharmacological receptors involved in these mepyramine-sensitive histamine responses have been defined as H-1 receptors (Ash, A. S. F. and H. O. Schild, Brit. J. Pharmacol Chemother., Vol. 27 (1966), p. 427. Histamine also stimulates the secretion of acid by the stomach (Loew, E. R. and O. Chickering, Proc. Soc. Exp. Biol. Med., Vol. 48 (1941), p. 65), increases the heart rate (Trendelenburg, U., J. Pharmacol., Vol. 130 (1960), p. 450), and inhibits contractions in the rat uterus (Dews, P. B. and J. D. P. Graham, Brit. J. Pharmacol. Chemother., Vol. 1 (1946), p. 278); these actions cannot be antagonized by mepyramine and related drugs. The H-2 antagonists useful in the oral care compositions or substances are those that blockade the receptors involved in mepyramine-insensitive, non-H-1 (H-2), histamine responses, and do not blockade the receptors involved in mepyramine-sensitive histamine responses.
Selective H-2 antagonists are those compounds found to be H-2 antagonists through their performance in classical preclinical screening tests for H-2 antagonist function. Selective H-2 antagonists are identified as compounds which can be demonstrated to function as competitive or non-competitive inhibitors of histamine-mediated effects in those screening models specifically dependent upon H-2 receptor function, but to lack significant histamine antagonist activity in those screening models dependent upon H-1 receptor function. Specifically, this includes compounds that would be classified as described by Black, J. W., W. A. M. Duncan, C. J. Durant, C. R. Ganellin and E. M. Parsons, xe2x80x9cDefinition and Antagonism of Histamine H2-Receptorsxe2x80x9d, Nature, Vol. 236 (Apr. 21, 1972), pp. 385-390 (Black), as H-2 antagonists if assessed as described by Black through testing with the guinea pig spontaneously beating right atria in vitro assay and the rat gastric acid secretion in vivo assay, but shown to lack in significant H-1 antagonist activity relative to H-2 antagonist activity, if assessed as described by Black with either the guinea pig ileum contraction in vitro assay or the rat stomach muscle contraction in vivo assay. Preferably selective H-2 antagonists demonstrate no significant H-1 activity at reasonable dosage levels in the above H-1 assays. Typical reasonable dosage level is the lowest dosage level at which 90% inhibition of histamine, preferably 99% inhibition of histamine, is achieved in the above H-2 assays.
Selective H-2 antagonists include compounds meeting the above criteria which are 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, DA4634, bisfentidine, sufotidine, ebrotidine, HE-30-256, D-16637, FRG-8813, FRG-8701, impromidine, L-643728, and HB-408. 4. 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 Index, 11th edition (1989), p. 354 (entry no. 2279), and Physicians"" Desk Reference, 46th edition (1992), p. 2228. Related preferred H-2 antagonists include burimamide and metiamide.
10. Analgesic Actives
Anti-pain or desensitizing 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.
11. Anti-viral Actives
Antiviral actives useful in the present composition include any know actives that are routinely use to treat viral infections. Such anti-viral actives are disclosed in Drug Facts and Comparisons (loose leaf drug information service), Wolters Kluer Company, St. Louis, Mo., (copyright)1997, pp. 402(a)-407(z), incorporated herein by reference in its entirety. Specific examples include anti-viral actives disclosed in U.S. Pat. No. 5,747,070, issued May 5, 1998 to Satyanarayana Majeti, incorporated herein by reference in its entirety. Said Patent discloses the use of stannous salts to control viruses. Stannous salts and other anti-viral actives are described in detail in Kirk and Othmer, Encyclopedia of Chemical Technology, Third Edition, Volume 23, Wiley-Interscience Publishers (1982), pp. 42-71, incorporated herein by reference in its entirety. The stannous salts that may be used in the present invention would include organic stannous carboxylates and inorganic stannous halides. While stannous fluoride may be used, it is typically used only in combination with another stannous halide or one or more stannous carboxylates or another therapeutic agent.
12. Other Ingredients
In addition to the above materials of the composition of the present invention, a number of other components may desirably be added to the oral care substance. Additional components include, but are not limited to, flavoring agents, sweetening agents, xylitol, opacifiers, coloring agents, surfactants, and chelants such as ethylenediaminetetraacetic acid. Suitable flavoring agents include, but are not limited to, oil of peppermint, oil of sassafras, clove bud oil, peppermint, menthol, anethole, thymol, methyl salicylate, eucalyptol, cassia, 1-menthyl acetate, sage, eugenol, parsley oil, oxanone, oil of wintergreen, alpha-irisone, oil of spearmint, marjoram, lemon, orange, propenyl guaethol, cinnamon, and mixtures thereof.
Pigments may also added to the compositions herein to more precisely indicate the locations at which the composition has actually been applied, allowing the user to apply the composition more thoroughly or evenly. However, such pigments are not intended to mask stains that may exist on the tooth surfaces.
These additional ingredients can also be used in place of the compounds disclosed above.

Systems comprising organosiloxane resins for delivering oral care substances and for prolonging such delivery


A signal processing system in which a differentially quantized digital signal is used, the digital signal having two bits which represent only three values, of which one value (10 or 01) is zero and the other two (11 and 00) values represent a positive value and a negative value respectively.

1. Field of the Invention
The present invention relates to a digital signal processor. A preferred embodiment of the invention relates to a digital audio signal processor. For convenience, reference will be made herein to audio signal processing, but the invention is not limited to audio signals.
2. Description of the Prior Art
It is well known to convert analogue signals to digital signals using differential quantization. In differential quantization a signal is sampled, and the difference between the value of a sample and a prediction of the value of the sample is quantized. The prediction may be the previous sample.
In general principle the difference can be quantized and represented by an m-bit signal where m is any integer, greater than or equal to one.
Common values of m in practice include 1, 8 and 16. Except for m=1, the differences are represented by signed numbers, e.g. 2""s complement numbers. A 1-bit signal represents 2 signal levels. Greater numbers of bits represent greater numbers of levels. For example an 8 bit signal represents 256 levels.
A 1-bit digital audio signal processor has been proposed in for example GB-A-2 319 931. The processor includes Delta-Sigma Modulator (DSM) filter sections. A 1-bit digital signal processor produces a 1-bit output that contains an audio signal which is obscured by quantization noise to an unacceptable level. It is imperative that the noise spectrum is suitably shaped to place as much of the noise as possible outside the audio signal band. The noise is produced mainly by the quantization of the audio signal to 1-bit.
A DSM filter section is designed to suitably shape the noise to minimise the noise in the audio band. A DSM filter section typically includes, amongst other circuits, at least one multiplier and a quantizer. The multiplier forms the product of an n-bit coefficient and the 1-bit signal. The quantizer re-quantizes the product as a 1-bit signal. The other circuits of a DSM filter section typically include delay elements and adders.
Whilst processing a 1-bit signal involves difficult quantization noise shaping it has advantages of simplicity of hardware. A 1-bit multiplier for example is a relatively simple circuit. Furthermore a 1-bit signal processor has the known advantages of an inherently serial structure, and a phase response and distortion approaching that of a high quality analogue system whilst retaining the advantages of digital techniques.
It is desired to reduce quantization noise and yet retain the many benefits of a 1-bit signal processing system.
According to one aspect of the present invention, there is provided a digital signal processing system in which differentially quantized data is represented by a 2-bit digital signal representing only 3 levels of which one level is zero and the other 2 levels are more positive and more negative respectively than zero.
The provision of such a differentially quantized digital signal, referred to hereinafter as a xe2x80x9cternary signalxe2x80x9d, having 2 bits representing only 3 levels produces better signal to noise ratio than a 1-bit signal, making a DSM filter section easier to design for the purpose of noise shaping. Also with the 2 bit representation of the 3 levels, in a preferred embodiment, only a minimal modification needs to be made to the multiplier(s) and the quantizer of what is otherwise a DSM filter section of a 1-bit signal processor. The modification is very cost effective.
The three levels may be represented by 11 for a positive increment relative to zero, 00 for a negative increment relative to zero and 01 or 10 for zero. It will be noted that two signal lines of a 2-bit parallel bus carrying the two bits may be reversed without affecting the values represented by the ternary signal.
The ternary signal used in the present invention differs from a xe2x80x9cconventionalxe2x80x9d 2 bit signal in that a conventional 2 bit signal represents four levels represented by 00, 01, 10, 11 respectively. The represented levels are either asymmetric with respect to zero or none of them represents zero per se. A signal processor using such a conventional 2 bit signal requires more gates than the ternary signal used in the present invention and is thus less cost effective than the present invention.
According to another aspect of the invention, there is provided a signal processing system comprising a plurality of Delta Sigma Modulators (DSMs) in cascade, at least one of the DSMs being arranged to receive an r bit signal and to output a q bit signal, where at least one of r and q is a ternary signal having two bits which represent only three values, of which one value is zero, and the other two values represent a positive value and a negative value respectively.
The ternary signal reduces high frequency noise, allowing the design of cascaded DSMs to be simpler because noise induced instability is reduced.

Signal processing system employing two bit ternary signal


The invention relates to use of ibandronic acid (1-hydroxy-3-(N-methyl-N-pentyl)aminopropyl-1,1-diphosphonic acid) or physiologically compatible salts or esters thereof for improving the osseointegration of cement-free anchored endoprostheses. Ibandronate or salts thereof is applied for a short time immediately after insertion of an endoprosthesis, with the surprising result that secondary stability of the implant is obtained in only 5 weeks or less after the operation.

This Application is a 371 of PCT/EP99/09252 filed Nov. 29, 1999.
The invention relates to use of ibandronic acid (1-hydroxy-3-(N-methyl-N-pentyl)aminopropyl-1,1-diphosphonic acid) or physiologically compatible salts or esters thereof for improving the osseointegration of cement-free anchored endoprostheses. Ibandronate or salts thereof is applied for a short time immediately after insertion of an endoprosthesis, with the surprising result that secondary stability of the implant is obtained in only 5 weeks or less after the operation.
Bones serve mainly as a support, and consequently bone is frequently regarded as a simple building material. However, bone is a complicated biomaterial adapted to a wide variety of requirements, stimuli and noxae to which it is exposed. Endoprostheses are available as substitutes for bones and joints. However endoprostheses, even when biomechanically highly refined, do not have an active effect on the environmental and load factors.
Throughout the world, about 1.5 million hip-joint endoprostheses are implanted per year, including about 120,000 in Germany. There is also a considerable number of other joint prostheses, e.g. knee-joint, ankle-joint and shoulder-joint endoprostheses. It is expected that the number of primary-implanted endoprostheses, particularly the number needing to be changed, will continue to increase. Meanwhile even relatively young patients are provided with endoprostheses. The life expectancy of man is progressively increasing, so that in some cases up to 3 or 4 changes of prostheses may be expected for individual patients during their life. Cement-free implants are increasingly used in order to preserve bone substance during the first operation and particularly during any required replacement operations and because of the assumed longer survival time of the prostheses. Younger patients needing an endoprosthesis will profit in particular from this kind of tissue-preserving treatment. Longer-lasting endoprostheses are also necessary in view of increased life expectancy and for economic reasons.
Special consideration must therefore be given to the processes and morphological changes occurring in the time after the operation until final stabilisation of the implant bed in the bone, and to knowledge about the primary and secondary stability, particularly of cement-free endoprostheses, since cement-free anchoring of implants has become the preferred method.
xe2x80x9cPrimary stabilityxe2x80x9d of an implant is described as the situation directly after implantation of the prosthesis in the bone. The prosthesis, via its distal part, is anchored either in the intramedullary canal in the diaphysis (cortical bone) or in the proximal metaphysis of the trochanter prominence. This primary stability is only qualitative, since the prosthesis is not yet incorporated in the bone.
Secondary stability, particularly in the case of hip prostheses, is usually attained only a few months after the bone grows into the prosthesis surface (osseointegration). In addition therefore to qualitative stabilisation there is a quantitative component, ensuring long-term stability of the prosthesis.
The process from primary stability to secondary stability goes through various phases. The first phase after prosthesis implantation is characterised by partial death of bone. Immediately after the operation, most parts of the neighbouring bone are intact. The subsequent partial bone death occurs over a few millimetres in the immediate neighbourhood of the prosthesis interface (the contact surface between the prosthesis and the bone). Dilated vessels and infiltration of polymorphonucleic cells occurs quickly at the boundary between still-living bone and dead bone, followed by fibroblasts, osteoblasts and osteoclasts. Repair occurs during the next stage. The dead bone tissue is infiltrated by granulation tissue and connective tissue. Macrophages and giant cells are occasionally observed. Newly-formed bone is superposed on the dead bone.
The third phase can last up to 2 years, during which the prosthesis is stabilised. During this time the dead bone material disintegrates and is replaced by woven and lamellar bone. At the end of the reconstruction process a narrow seam of connective tissue is frequently left between the bone and the smooth surface of the prosthesis. These phases are also influenced by the individual characteristics of the patient such as bone metabolism (osteoporotic, osteopenic, juvenile) and extrinsic factors such as relief of stress on the prosthesis after the operation and the form of rehabilitation.
The disadvantages of cement-free anchoring, as opposed to the cemented method, according to existing knowledge is that secondary stabilisation of a prosthesis occurs after a period of not less than 6-8 weeks.
Hofmann et al. (Progression of human bone ingrowth into porous-coated implants. Acta Orthop Scan 1997; 68 (2):161-166 discloses that the secondary stabilising of hip prostheses takes up to 9 months. The results of his study are explained by the fact that the ingrowth of human trabecula bone occurs at a speed of about 1 micrometer per day. The maximum attainable ingrowth of the prosthesis occurs not before 9 months after the operation, even if surface-treated prostheses are used. This agrees with the observation of Krxc3xcger et al. (Teilbelastng oder Vollbelastungxe2x80x94Therapiestrategie nach zementfreier Hxc3xcfttotalendoprothese Orthop Praxis 1998; 34 (5):287-293). In all cases Krxc3xcger noted additional sintering of the prosthesis shank during the first 6 months after the operation, with formation of a delicate sclerosis line in the Gruen zone 1. Also Wall et al. (Auswertung der Osseointegration von zementlosen Hxc3xcftprothesenstielen mit Computerauswertung digitaler Rxc3x6ntgendensitometrie Orthop. Praxis 34:73-77 1998) showed a decrease of 18% in the optical density of the bone tissue in all Gruen zones during the first 6 months after the operation, irrespective of which of the two types of prosthesis was investigated. Only thereafter was there a renewed increase of bone density, for 24 months after the operation only a starting value of 92 to 97% had been reached. In many centres, therefore, patients keep the operated leg stress-free for up to 6 months after the operation. This is to prevent the prosthesis sinking further into the bone or causing fractures.
According to Burke et al. (Micromotion of cemented and uncemented femoral components. J Bone Joint Surg 73B:33-38 1991) secondary integration of the bone into the prosthesis, disturbed by pathological micromovements ( greater than 150 micrometers) results in formation of connective tissue on the interface between the bone and prosthesis. This, and the resulting fear of fractures, make it necessary to relieve stress on the prosthesis for a prolonged period. This greatly slows the rehabilitation of patients, and may result in more and longer-lasting complaints.
On the other hand, a reduced mechanical load on the bone (stress shielding) results in periprosthetic bone atrophy, which may last up to a year and is regarded as a reason for premature loosening of the cement-free prosthesis.
The operations, the duration of post-operative after-treatment in clinics, the non-productive time during the rehabilitation phase, re-integration of younger patients in the work progress and subsequent operations result in enormous costs to the community.
The main proposals hitherto for improving the early and long-term results after endoprosthetic replacement are: improving the design of prostheses with proximal introduction of force, rotational stability, surface coatings and press fit of cement-free endoprostheses. In present clinical treatment there is no use of drugs for increasing the ingrowth of endoprostheses, although the use of growth factors (e.g. BMPs) in conjunction with cement-free implants has been studied in recent research (Proceedings of the annual meeting of the ORS 5, 245, 339, 599 1998 New Orleans).
On the other hand drugs from the amino-bisphosphonate group have a positive influence on xe2x80x9cbone remodellingxe2x80x9d and produce an increase in bone mass and bone quality, particularly in osteoporosis research. Pre-clinical knowledge of biological and physical properties of bisphosphonates has been available for about 30 years.
Each bisphosphonate has its own chemical, biological and physiological properties and consequently its own activity profile. Bisphosphonates can be used inter alia in bone surgery.
For example, use of bisphosphonates in bone surgery is known from WO 94/21266 A1. Clodronate in particular is used before and/or after a transplantation operation to increase the formation of bone tissue and/or to eliminate complications after implantation. A daily dose of 0.01-100 mg/kg is disclosed, preferably 0.5-20 mg/kg for parenteral use, 0.5-5 mg/kg for i.v. application and 10-100 mg/kg for oral use.
It is recommended to begin treatment 1 to 3 weeks before the operation and/or to continue for preferably 1 to 6 months after an operation. In the case of bone transplantation, it was shown that after 35 days new bone formation occurred in nearly all the transplants in the treated animals. It was shown, with reference to an explanted bone-tooth implant, that after treatment with Clodronate for 4 weeks (1 week before the operation and 3 weeks after), osteogenesis (bone formation) is more intensive than in patients not treated with Clodronate.
Bisphosphonates for treatment and/or prevention of loosening and migration of endoprostheses are described in WO 94/30421 A1, WO 95/28936 A1 and U.S. Pat. No. 5,646,134.
According to WO 95/30421 A1, it is recommended to prevent loosening and migration of prostheses by administering a bisphosphonate before, during and after the operation. The proposed dosage is between 0.002 and 3.40 mg/kg, preferably 0.01-2.40 mg/kg, administered continuously, i.e. daily or at cyclic intervals. Tested animals (sheep) were treated with a bisphosphonate i.v. immediately after the operation. If required the treatment should be continued at intervals, e.g. every 4 or 8 weeks. The seat of the prosthesis was checked monthly and after a year, further checks showed that the compounds gave suitable protection from loosening of prostheses. No detailed results, have been disclosed. It is also not stated what substances were used. Since the embodiments show forms of administration of pamidronate, risedronate and EB 1053, it is assumed that these compounds are preferred.
According to WO 95/28936 A1 and U.S. Pat. No. 5,646,134 bisphosphonates, preferably alendronate, are used to prevent periprosthetic bone loss by inhibiting bone resorption, and for reducing the pain associated with bone loss. Alendronate is applied preferably orally or parenterally, or alternatively the orthopaedic implant can be coated with a bisphosphonate in order to increase the fastening to the bone during the operation. The effective dosage is at 1.5 to 3000 xcexcg/kg body weight, preferably 10 xcexcg/kg. Bone resorption cannot be stopped completely but is considerably slowed down by treatment with higher doses of alendronate.
The object of the invention is to improve the osseointegration of endoprostheses by attaining secondary stability as quickly as possible and thus speeding up the rehabilitation of patients.
It has unexpectedly been found that osseointegration of endoprostheses, particularly joint prostheses such as knee-joint, ankle-joint or shoulder-joint endoprostheses and particularly preferably hip-joint prostheses, is accelerated and secondary stabilisation of the prosthesis is attained after only 5 weeks, preferably after 2 to 4 weeks, by short-term application, directly after the operation, of ibandronic acid (1-hydroxy-3-(N-methyl-N-pentyl)aminopropyl-1,1-diphosphonic acid) or physiologically compatible salts or esters thereof. xe2x80x9cOsseointegrationxe2x80x9d means a direct structural and functional connection between vital bone and the surface of implants under load.
Short-term administration of ibandronate, beginning during the operation, for a period of about 2-4 weeks and 1 to 7 times per week or at cyclic intervals (depending on the individual characteristics of the patient such as age, sex and bone metabolism (osteoporotic, osteopenic, juvenile)) prevents the bone resorption caused by osteoclasts and, owing to predominance of the osteoblastic reaction, promotes an increase in bone growth on the prosthesis. The result is a rapid increase in bone mass around the prosthesis. Administration of ibandronate results in formation of a larger amount of integrated bone, earlier maturation thereof, and avoidance of osteopenia around the prosthesis. Since the duration of reduced mechanical load on the intact bones of the patient, particularly in the case of hip-joint operations, could be considerably reduced, the risk of bone atrophy was zero or negligible.
Preferably the sodium salt of ibandronic acid is used.
Ibandronic acid or pharmaceutically acceptable salts thereof, preferably the sodium salt, are well known in the art. Ibandronic acid or pharmaceutically acceptable salts thereof have been described for example in European Patent Application No. 252,504 and U.S. Pat. No. 4,927,814.
Ibandronic acid or pharmaceutically acceptable salts thereof can be administered as liquids, solids or orally in aerosol form, or enterally, parenterally, topically, nasally, pulmonary or rectally in all conventional non-toxic pharmaceutically accepted excipients, adjuvants and additives. The term xe2x80x9cparenteralxe2x80x9d includes subcutaneous, intravenous and intramuscular administration or infusions. Oral forms of application can be e.g. tablets, capsules, dragees, syrups, solutions, suspensions, emulsions, elixirs, etc., which can contain one or more additives out of the following groups, e.g. flavourings, sweeteners, dyes and preservatives. Oral forms of application contain the active component together with non-toxic pharmaceutically accepted excipients suitable for producing tablets, capsules, dragees etc., such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; starch, mannitol, methyl cellulose, talc, highly dispersed silicic acids, higher-molecular fatty acids (such as stearic acid), peanut oil, olive oil, paraffin, miglyol, gelatine, agar, magnesium stearate, beeswax, cetyl alcohol, lecithin, glycerol, animal or vegetable fats, or solid high-molecular polymers such as polyethylene glycols. Tablets, capsules, dragees etc. can be given a suitable coating e.g. of glyceryl monostearate or glyceryl distearate in order to prevent undesired side-effects in the stomach, or to delay absorption in the gastro-intestinal tract and thus prolong the period of action. The preferred media for injection are sterile injectable aqueous or oily solutions or suspensions containing the usual additives such as stabilisers and solubilisers if required. Examples of such additives are water, isotonic common-salt solution, 1,3-butanediol, fatty acids such as oleic acid, monodiglycerides, diglycerides or miglyol. Rectal use can be made of all suitable non-irritant additives which are solid at normal temperature and liquid at rectal temperature, e.g. cocoa butter or polyethylene glycol. Usual pharmaceutical excipients can be applied in aerosol form. Creams, tinctures, gels, solutions or suspensions etc. with usual pharmaceutical additives are of use externally.
Accordingly, the present invention comprises the use of ibandronic acid or physiologically compatible salts or esters thereof for improving the osseointegration of cement-free anchored endoprostheses by short-term application directly after the operation and within two to four weeks.
++The daily i.v. equivalent dosage for ibandronate is preferably 0.1 xcexcg/kg to 100 xcexcg/kg body weight, preferably 1 to 100 xcexcg/kg body weight. A daily dose of 20 to 30 xcexcg/kg body weight is particularly preferred, and results in complete integration after only 15-20 days.
When used according to the invention, ibandronate is preferably in the form of a solution for parenteral application, containing the active substance in a proportion of 0.01-20 mg.
When using other forms of application, the dosage must be adjusted in accordance with the bioavailability of the application form.
The present invention thus relates particularly to the use of ibandronic acid or its physiological compatible salts, preferably the sodium salt, or esters to improve osseointegration of cement-free anchored endoprostheses by short-term direct post-operative application within a period of two to four weeks. Ibandronate can be used in a dose of 0.1 to 100 xcexcg/kg body weight, preferably 1 to 100 xcexcg/kg bodyweight. Ibandronate can also be applied as a solution for parenteral use with an active substance content of 0.01 to 20 mg. The application can be made one to seven times per week. The use of ibandronic acid as described can also be effected by intermittent cyclic application. The said uses are characterised in that the osseointegration of hip joint endoprostheses is improved. The invention also relates to the use of ibandronic acid or its physiological compatible salts or esters to establish secondary stability of hip joint endoprostheses in a period of xe2x89xa65 weeks after the operation. The use is characterised in that the secondary stability is achieved after two to four weeks.
The invention will now be explained in further detail with reference to exemplified embodiments.

Use of ibandronate for promoting osseointegration of endoprostheses


A timing light for measuring timing of spark ignition has separate displays of engine RPM and timing advance. Another aspect of the invention provides a flashlight function which triggers the flash tube of the timing light to produce a constant bright light source for locating timing marks within an engine compartment. The flashlight function can be incorporated into a dual display digital timing light, or other timing light designs. A dedicated control on the timing light functions to place the flash tube in a continuous flashlight mode.

The present invention pertains generally to electronic testing equipment and, more particularly, to electronic instruments for monitoring or measuring the performance of machinery such as internal combustion engines.
Precise ignition timing and idle adjustments are essential in order to achieve maximum fuel economy and performance in internal combustion engines. Because timing changes with engine RPM and load, it is important to be able to measure timing not only at initial or base timing, as is done with a conventional timing light, but also to be able to measure timing advance, which is possible with digital timing lights and advance timing lights. Most engines require that both initial and advance timing calibrations be set or checked at specific engine RPMs, or in some cases with a specific vacuum applied to the vacuum advance diaphragm on the distributor, or in some cases by the vehicle""s onboard computer. In the case of engines which are equipped with breaker point ignition systems, it will be necessary to set point dwell before adjusting timing.
Car manufacturers specify engine timing measured in degrees at certain engine speeds measured in RPM. Engine speed has to be maintained at a specified value for the timing reading to be valid. On a conventional digital timing light, the operator uses a switch to manually toggle a single display between the tachometer mode (reading engine RPM) and the timing mode (reading timing in degrees of advance).
Prior to beginning the timing check procedure, the stationary timing mark located on the engine must be found. On some engines, finding the timing mark is difficult or even impossible without a flashlight or some other source of light. Several timing light models available on the market have a small flashlight integrated into the case. The flashlight consists of an incandescent bulb, a lens, a bulb holder, an on/off switch, and some miscellaneous wires. The disadvantages of this design are that the light produced by the bulb is not very bright, the light bulb needs to be replaced periodically when it fails due to burning up or filament breakage due to a mechanical shock. Adding this feature also significantly increases the cost.
In the proposed design, the flash tube normally used to produce a strobe of light for engine timing measurements is also used to illuminate the engine compartment when looking for the timing marks. Depressing the flashlight button will interrupt the normal mode of operation and cause the flash tube to flash at a relatively high rate of approximately, for example, 25 Hz or higher regardless of the engine speed. At this high flashing rate, the human eye will perceive the light spot created by the flash tube and the lens in front of it as light essentially without flicker. When the flashlight button is released, the timing light switches back to normal mode of operation.
In a microcontroller or microprocessor controlled timing light, a flashlight on/off switch is required to add the flashlight feature of the invention. The software of a microcontroller or microprocessor controlled timing light generates a signal to trigger the flash tube at a relatively high rate to produce a light which is perceived by the human eye as continuous or constant. In other timing light designs, a flashlight on/off switch and a small circuit need to be added. This circuit will generate a square wave with a frequency of 25 Hz or higher to drive the flash-tube triggering circuit. The advantages of the new design are; brighter light (since the Xenon flash tubes produce brighter light than small incandescent bulbs); fewer parts, lower cost, and higher reliability since no additional parts are needed (light bulb, bulb holder, and lens, etc.).
A digital timing light with two displays simultaneously presenting engine speed and timing simplify the operation and allow to monitor engine speed constantly during the process of measuring the timing. This is especially useful for a one-person operation when a mechanic needs to manually operate the throttle with one hand to maintain proper engine speed, point the flashing light at the stationary and moving timing marks, operate the Increase and Decrease Advance switches, and read the displays. In accordance with several objects of the invention, there is provided a device for measuring and displaying information pertaining to the operation of a spark-ignited internal combustion engine, including a housing having a gripping portion and a pointing portion, a flash tube mounted within the pointing portion behind a lens at a distal end of the pointing portion, the flash tube electrically connected to a control circuit operative to sense electrical pulses from an engine and to control a triggering voltage supplied to the flash tube, a first display in the housing connected to the control circuit and operative to display a running speed of an engine, and a second display in the housing connected to the control circuit and operative to display an indication of timing of an engine.

Engine timing measurement device with RPM and advance displays and flashlight function