A negative-working heat-sensitive material for making a lithographic printing plate by direct-to-plate recording is disclosed which comprises in the order given a lithographic base having a hydrophilic surface, an oleophilic imaging layer and a cross-linked hydrophilic upper layer, characterize in that the oleophilic imaging layer comprises at least one transition metal complex of an organic acid. Materials according to the invention are characterized by an increased run length and can be used as a printing plate immediately after exposure.

The present invention relates to a negative-working heat-sensitive material which is suitable for making a lithographic printing plate by direct-to-plate recording and to a method for imaging said heat-mode recording material by means of an infrared laser.
Lithographic printing is the process of printing from specially prepared surfaces, which contain a lithographic image consisting of areas that are capable of accepting ink (oleophilic areas) and areas that do not accept ink but are water-accepting (hydrophilic areas). In so-called wet lithographic printing methods, both water or an aqueous dampening liquid (also called fountain solution) and ink are applied to the plate surface that contains the hydrophilic and oleophilic areas. The hydrophilic areas are soaked with water or the dampening liquid and are thereby rendered oleophobic.
Various heat-mode plate materials are known which can be used as a lithographic master for printing with greasy inks. Ablative plates are the best known examples of so-called processless plates, i.e. plates which do not require any processing and therefore can be used as a printing plate immediately after exposure. The heat, which is generated in the recording layer of such ablative plates by light absorption of a laser beam, removes a hydrophilic or oleophilic topcoat to expose an underlying oleophilic respectively hydrophilic surface, thereby obtaining the necessary differentiation of ink-acceptance between the image (printing) and non-image or background (non-printing) areas.
For example DE-A-2 448 325 discloses a laser heat-mode xe2x80x98direct negativexe2x80x99 printing plate comprising e.g. a polyester film support provided with a hydrophilic surface layer. The disclosed heat-mode recording material is imaged using an Argon laser thereby rendering the exposed areas oleophilic. An offset printing plate is thus obtained which can be used on an printing press without further processing. The plate is called a xe2x80x98direct negativexe2x80x99 plate because it is suitable for direct exposure by a laser beam (xe2x80x9ccomputer-to-platexe2x80x9d, no film mask required) and because the areas of the recording material that have been exposed to the laser are rendered ink-accepting and define the image areas, i.e. the printing areas.
Other disclosures in DE-A-2 448 325 concern xe2x80x9cdirect negativexe2x80x9d printing plates comprising e.g. hydrophilic aluminum support coated with a water soluble laser light (Argon-488 nm) absorbing dye or with a coating based on a mixture of hydrophilic polymer and laser light absorbing dye (Argon-488 nm). Further examples about heat-mode recording materials for preparing xe2x80x9cdirect negativexe2x80x9d printing plates have been described in e.g. DE-A-2 607 207, DD-A-213 530, DD-A-217 645 and DD-A-217 914. These documents disclose heat-mode recording materials that contain an anodized aluminum support and a hydrophilic recording layer provided thereon. Laser exposure renders the exposed areas insoluble and ink-receptive, whereas the non-exposed areas remain hydrophilic and water-soluble. Such plates can also be used directly on the press without processing, because the non-exposed areas are removed by the dampening liquid during printing, thereby revealing the anodized aluminum support.
DD-A-155 407 discloses a processless heat-mode xe2x80x98direct negativexe2x80x99 printing plate where a hydrophilic aluminum oxide layer is rendered oleophilic by direct laser heat-mode imaging.
The above heat-mode xe2x80x98direct negativexe2x80x99 lithographic printing plate are characterized by a low recording speed and/or the obtained plates are of poor quality and durability.
EP-A-580 393 discloses an ablative lithographic printing plate directly imageable by laser discharge, the plate comprising a topmost first layer and a second layer underlying the first layer wherein the first layer is characterized by efficient absorption of infrared radiation and the first and second layer exhibit different affinities for at least one printing liquid.
EP-A-683 728 discloses a heat-mode recording material comprising on a support having an ink receptive surface or being coated with an ink receptive layer a substance capable of converting light into heat and a hardened hydrophilic surface layer having a thickness not more than 3 xcexcm.
U.S. Pat. No. 4,034,183 describes a processless lithographic plate that comprises a light-absorbing hydrophilic top layer coated on a support which is exposed to a laser beam to convert the absorber from an ink repelling to an ink receiving state. All of the examples and teachings require a high power laser, and the run lengths of the resulting lithographic plates are limited.
U.S. Pat. No. 3,832,948 describes both a printing plate with a hydrophilic layer that may be ablated by strong light from a hydrophobic support and also a printing plate with a hydrophobic layer that may be ablated from a hydrophilic support. However, no examples are given.
U.S. Pat. No. 3,964,389 describes a processless printing plate based on the principle of laser transfer of material. This process is very sensitive to transfer defects and requires an additional donor sheet.
U.S. Pat. No. 4,054,094 describes a process for making a lithographic printing plate by using a laser beam to etch away a thin top coating of polysilicic acid on a polyester base, thereby rendering the exposed areas receptive to ink. No details of run length or print quality are given, but it is expected that an non-crosslinked polymer such as polysilicic acid will wear off rapidly and give a short run length.
U.S. Pat. No. 4,081,572 describes a method for preparing a printing master on a substrate by coating the substrate with a hydrophilic polyamic acid and then image-wise converting the polyamic acid to melanophilic polyimide with heat from a flash lamp or a laser. No details of run length, image quality or ink/water balance are given.
Japanese Kokai No. 55/105560 describes a method of preparation of a lithographic printing plate by laser beam removal of a hydrophilic layer coated on a melanophilic support, in which the hydrophilic layer contains colloidal silica, colloidal alumina, a carboxylic acid, or a salt of a carboxylic acid. The only examples given use colloidal alumina alone, or zinc acetate alone, with no crosslinkers or addenda. No details are given for the ink/water balance or limiting run length.
WO 92/09934 describes and broadly claims any photosensitive composition containing a photo acid generator, and a polymer with acid labile tetrahydropyranyl groups. This would include a hydrophobic/hydrophilic switching lithographic plate composition. However, such a polymeric switch is known to give weak differentiation between hydrophilic and oleophilic areas.
All the examples mentioned in the prior art fail to prepare a processless direct imageable printing plate which has a high sensitivity, good start-up behaviour and offers a high run length.
Unpublished EP-A no. 99202109, filed on Jun. 06, 1999, discloses a negative-working heat-sensitive material for making lithographic plates comprising in the order given a lithographic base having a hydrophilic surface, an oleophilic imaging layer and a cross-linked hydrophilic upper layer. The heat generated during exposure in the light-sensitive layer removes the hydrophilic upper layer by ablation. The oleophilic imaging layer has a thin coating thickness that is optimized for achieving a high run length. However when using such thin oleophilic layers, it was found that the run length of the image areas was still not satisfying, because of the effect of the hydrophilic support just below the thin oleophilic layer. This is especially the case when using long pixel dwell times as those for example on external drum laser recording equipment such as the Creo TrendSetter 3244 (drum rotating at 50 to 250 rpm)
It is an object of the present invention to provide a processless material that is suitable for heat-mode direct-to-plate recording and is characterized by a high sensitivity and a high lithographic quality, especially with regard to run length. It is also an object to provide a material that achieves the high run length when exposed in external drum (long pixel dwell time, low laser beam intensity) as well as internal drum laser recorders (short pixel dwell time, high laser beam intensity). These objects are realized by the material defined in claim 1. Preferred embodiments thereof are defined in the dependent claims.
The lithographic printing plate of the present invention comprises in the order given a lithographic base having a hydrophilic surface, an oleophilic imaging layer and a cross-linked hydrophilic upper layer. It has surprisingly been found that by the addition of even very small amounts of transition metal complexes of an organic acid in the oleophilic imaging layer, the run length of these plate increases substantially. Transition metals are generally defined as the elements of atomic numbers 21-31, 39-49 and 71-81. Chromium is highly preferred. Examples of these chromium complexes of organic acids are sold under the QUILON trade name by Dupont Corporation, such as QUILON C, a 25 to 30% by weight solution of the Werner complex of trivalent chromium and myristic or stearic acid in isopropyl alcohol, as described in Quilon chrome Complexes, Dupont Corporation, April, 1992.
The oleophilic imaging layer comprises a binder and a compound capable of converting light into heat.
Suitable compounds capable of converting light into heat are preferably infrared absorbing components having an absorption in the wavelength range of the light source used for image-wise exposure. Particularly useful compounds are for example dyes and in particular infrared dyes as disclosed in EP-A-908 307 and pigments and in particular infrared pigments such as carbon black, metal carbides, borides, nitrides, carbonitrides, and bronze-structured oxides. It is also possible to use conductive polymer dispersion such as polypyrrole, polyaniline, or polythiophene-based conductive polymer dispersions. Carbon black or graphite yield very good and favorable results.
The binder of the oleophilic imaging layer is preferably selected from the group consisting of polyvinyl chloride, polyesters, polyurethanes, novolac, polyvinyl carbazole, or copolymers or mixtures thereof. In a most preferred embodiment, the binder itself is heat-sensitive: e.g. a self-oxidizing polymer containing nitrate ester groups such as cellulose nitrate as disclosed in GB-P-1 316 398 and DE-A-2 512 038; a polymer containing carbonate groups such as polyalkylene carbonate; or a polymer containing covalently bound chlorine such as polyvinylidene chloride. Also substances containing azo or azide groups, capable of liberating N2 upon heating are favorably used.
The dry coating weight of the oleophilic imaging layer is preferably between 0.10 and 0.75 g/m2, more preferably between 0.15 and 0.50 g/m2.
The cross-linked hydrophilic upper layer is preferably coated from aqueous compositions containing hydrophilic binders having free reactive groups including e.g. hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl, etc., along with suitable crosslinking or modifying agents including e.g. hydrophilic organotitanium reagents, aluminoformyl acetate, dimethylol urea, melamines, aldehydes, hydrolyzed tetraalkyl orthosilicate, etc. Suitable hydrophilic binders for use in the upper layer may be selected from the group consisting of gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and the salts thereof, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and salts thereof, polymethacrylic acids and salts thereof, hydroxyethylene polymers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols and hydrolyzed polyvinylacetate having a hydrolyzation degree of at least 60% by weight and more preferably at least 80% by weight.
Hydrophilic layers containing polyvinylalcohol or polyvinylacetate hydrolyzed to an extent of at least 60% by weight hardened with a tetraalkyl orthosilicate, e.g. tetraethyl orthosilicate or tetramethyl orthosilicate, as disclosed in e.g. U.S. Pat. No. 3,476,937, are particularly preferred because their use in the present heat-mode recording material results in excellent lithographic printing properties.
A further suitable cross-linked hydrophilic layer is disclosed in EP-A-514 990. The layer disclosed in this EP-application comprises the hardening reaction product of a (co)polymer containing amine or amide functions having at least one free hydrogen (e.g. amino modified dextrane) and aldehyde.
The cross-linked hydrophilic upper layer preferably also contains substances that increase the mechanical strength and the porosity of the layer e.g. metal oxide colloid particles which are particles of titanium dioxide or other metal oxides. Incorporation of these particles gives the surface of the cross-linked hydrophilic layer a uniform rough texture consisting of microscopic hills and valleys. These particles are preferably oxides or hydroxides of beryllium, magnesium, aluminum, silicon, gadolinium, germanium, arsenic, indium, tin, antimony, tellurium, lead, bismuth or a transition metal. Particularly preferable colloid particles are oxides or hydroxides of aluminum, silicon, zirconium and titanium, used in 20 to 95% by weight of the hydrophilic layer, more preferably in 30 to 90% by weight of the hydrophilic layer.
The cross-linked hydrophilic upper layer is preferably coated at a dry thickness of 0.3 to 5 xcexcm, more preferably at a dry thickness of 0.5 to 3 xcexcm.
The cross-linked hydrophilic upper layer may further comprise additional substances such as e.g. plasticizers, pigments, dyes etc. The cross-linked hydrophilic upper layer may also contain an IR-absorbing compound in order to increase the IR-sensitivity. Particular examples of suitable cross-linked hydrophilic layers for use in accordance with the present invention are disclosed in EP-A-601 240, GB-P-1 419 512, FR-P-2 300 354, U.S. Pat. No. 3,971,660, and U.S. Pat. No. 4,284,705.
According to the present invention, the lithographic base may be an anodized aluminum support. A particularly preferred lithographic base is an electrochemically grained and anodized aluminum support. The anodized aluminum support may be treated to improve the hydrophilic properties of its surface. For example, the aluminum support may be silicated by treating its surface with a sodium silicate solution at elevated temperature, e.g. 95xc2x0 C. Alternatively, a phosphate treatment may be applied which involves treating the aluminum oxide surface with a phosphate solution that may further contain an inorganic fluoride. Further, the aluminum oxide surface may be rinsed with a citric acid or citrate solution. This treatment may be carried out at room temperature or may be carried out at a slightly elevated temperature of about 30 to 50xc2x0 C. A further interesting treatment involves rinsing the aluminum oxide surface with a bicarbonate solution. Still further, the aluminum oxide surface may be treated with polyvinylphosphonic acid, polyvinylmethylphosphonic acid, phosphoric acid esters of polyvinyl alcohol, polyvinylsulphonic acid, polyvinylbenzenesulphonic acid, sulphuric acid esters of polyvinyl alcohol, and acetals of polyvinyl alcohols formed by reaction with a sulphonated aliphatic aldehyde It is further evident that one or more of these post treatments may be carried out alone or in combination. More detailed descriptions of these treatments are given in GB-A-1 084 070, DE-A-4 423 140, DE-A-4 417 907, EP-A-659 909, EP-A-537 633, DE-A-4 001 466, EP-A-292 801, EP-A-291 760 and U.S. Pat. No. 4,458,005.
According to another mode in connection with the present invention, the lithographic base can also be a flexible support, which is provided with a hydrophilic layer, hereinafter called xe2x80x98base layerxe2x80x99. The flexible support is e.g. paper, plastic film or aluminum. The base layer is preferably a cross-linked hydrophilic layer obtained from a hydrophilic binder cross-linked with a hardening agent such as formaldehyde, glyoxal, polyisocyanate or a hydrolysed tetra-alkylorthosilicate. The latter is particularly preferred.
The hydrophilic binder for use in the base layer is e.g. a hydrophilic (co)polymer such as homopolymers and copolymers of vinyl alcohol, acrylamide, methylol acrylamide, methylol methacrylamide, acrylate acid, methacrylate acid, hydroxyethyl acrylate, hydroxyethyl methacrylate or maleic anhydride/vinylmethylether copolymers. The hydrophilicity of the (co)polymer or (co)polymer mixture used is preferably the same as or higher than the hydrophilicity of polyvinyl acetate hydrolyzed to at least an extent of 60% by weight, preferably 80% by weight.
The amount of hardening agent, in particular tetraalkyl orthosilicate, is preferably at least 0.2 parts per part by weight of hydrophilic binder, more preferably between 0.5 and 5 parts by weight, most preferably between 1 parts and 3 parts by weight.
The hydrophilic base layer may also contain substances that increase the mechanical strength and the porosity of the layer. For this purpose colloidal silica may be used. The colloidal silica employed may be in the form of any commercially available water dispersion of colloidal silica for example having an average particle size up to 40 nm, e.g. 20 nm. In addition inert particles of larger size than the colloidal silica may be added e.g. silica prepared according to Stxc3x6bber as described in J. Colloid and Interface Sci., Vol. 26, 1968, pages 62 to 69 or alumina particles or particles having an average diameter of at least 100 nm which are particles of titanium dioxide or other heavy metal oxides. By incorporating these particles the surface of the hydrophilic base layer is given a uniform rough texture consisting of microscopic hills and valleys, which serve as storage places for water in background areas.
The thickness of the hydrophilic base layer may vary in the range of 0.2 to 25 xcexcm and is preferably 1 to 10 xcexcm.
Particular examples of suitable hydrophilic base layers for use in accordance with the present invention are disclosed in EP-A-601 240, GB-P-1 419 512, FR-P-2 300 354, U.S. Pat. No. 3,971,660, and U.S. Pat. No. 4,284,705.
As flexible support of a lithographic base in connection with the present embodiment it is particularly preferred to use a plastic film e.g. polyethylene terephthalate film, polyethylene naphthalate film, cellulose acetate film, polystyrene film, polycarbonate film, etc. The plastic film support may be opaque or transparent.
It is particularly preferred to use a film support to which an adhesion improving layer, also called substrate layer, has been provided. Particularly suitable adhesion improving layers for use in accordance with the present invention comprise a hydrophilic binder and colloidal silica as disclosed in EP-A-619 524, EP-A-620 502 and EP-A-619 525. Preferably, the amount of silica in the adhesion improving layer is between 200 mg per m2 and 750 mg per m2. Further, the ratio of silica to hydrophilic binder is preferably more than 1 and the surface area of the colloidal silica is preferably at least 300 m2 per gram, more preferably at least 500 m2 per gram.
Optionally the heat-sensitive imaging material can be covered with an additional hydrophilic layer, provided on top of the hydrophilic upper layer discussed above, which comprises an organic compound containing cationic groups as described in EP-A no. 99202110, filed on Jun. 29, 1999.
In accordance with the method of the present invention, the imaging material is image-wise exposed to cause removal of the cross-linked hydrophilic upper layer and whereby the exposed areas are converted to oleophilic areas while the unexposed areas remain hydrophilic. This is mostly the case when using short pixel dwell times (for example 1 to 100 ns). However when using longer pixel dwell times (for example 1 to 20 xcexcs) the hydrophilic layer may not completely be removed upon exposure. The remaining parts of the hydrophilic layer can then be removed on the press by contact with fountain solution and ink or by an additional wet or dry processing step between the IR-laser exposure and the start-up of the printing process. A suitable dry processing step is e.g. mechanical treatment such as rubbing or brushing the layer with e.g. a cotton path. A preferred additional wet processing step is a gumming step as is commonly used for conventional plates. A gumming step is normally not regarded as a processing step, but rather as a treatment which protects the hydrophilic areas from fingerprints or other contamination which may affect the water-acceptance of these areas. Upon gumming the remaining ablation dust on the plate is removed thereby avoiding contamination of the press. At the same time the hydrophilic areas are covered with a thin layer of the gumming solution inducing a better start-up performance.
Image-wise exposure in connection with the present invention is preferably an image-wise scanning exposure involving the use of a laser or L.E.D. Preferably lasers are used that operate in the infrared or near-infrared, i.e. wavelength range of 700-1500 nm. Most preferred are laser diodes emitting in the near-infrared with an intensity higher than 0.1 mW/xcexcm2.
According to the present invention the plate is then ready for printing without an additional development and can be mounted on the printing press.
According to a further method, the imaging material is first mounted on the printing cylinder of the printing press and then image-wise exposed directly on the press by means of an integrated image recording device. Subsequent to exposure, the imaging material is ready for printing.
The printing plate of the present invention can also be used in the printing process as a seamless sleeve printing plate. In this option the printing plate may be soldered in a cylindrical form by means of a laser. Such cylindrical printing plate which has as diameter the diameter of the print cylinder can be slid on the print cylinder instead of mounting a conventional printing plate. More details on sleeves are given in xe2x80x9cGrafisch Nieuwsxe2x80x9d, 15, 1995, page 4 to 6.
The following example illustrates the present invention without limiting it thereto. All parts and percentages are by weight unless otherwise specified.


Branched, substantially non-antigenic polymers are disclosed. Conjugates prepared with the polymers and biologically active molecules such as proteins and peptides demonstrate extended circulating life in vivo. Substantially fewer sites on the biologically active material are used as attachment sites. Methods of forming the polymer, conjugating the polymers with biologically active moieties and methods of using the conjugates are also disclosed.

Field of the Invention
The present invention relates to branched polymers which are useful in extending the in vivo circulating life of biologically active materials. The invention also relates to conjugates made with the polymers.
Some of the initial concepts of coupling peptides or polypeptides to poly(ethylene glycol) PEG and similar water-soluble poly(alkylene oxides) are disclosed in U.S. Pat. No. 4,179,337, the disclosure of which is incorporated herein by reference. Polypeptides modified with these polymers exhibit reduced immunogenicity/antigenicity and circulate in the bloodstream longer than unmodified versions.
To conjugate poly(alkylene oxides), one of the hydroxyl end-groups is converted into a reactive functional group. This process is frequently referred to as xe2x80x9cactivationxe2x80x9d and the product is called an xe2x80x9cactivated poly(alkylene oxide)xe2x80x9d. Other substantially non-antigenic polymers are similarly xe2x80x9cactivatedxe2x80x9d or functionalized.
The activated polymers are reacted with a therapeutic agent having nucleophilic functional groups that serve as attachment sites. One nucleophilic functional group commonly used as an attachment site is the xcex5-amino groups of lysines. Free carboxylic acid groups, suitably activated carbonyi groups, oxidized carbohydrate moieties and mercapto groups have also been used as attachment sites.
Insulin and hemoglobin were among the first therapeutic agents conjugated. These relatively large polypeptides contain several free xcex5-amino attachment sites. A sufficient number of polymers could be attached to reduce immunogenicity and increase the circulating life without significant loss of biologic activity.
Excessive polymer conjugation and/or conjugation involving a therapeutic moiety""s active site where groups associated with bioactivity are found, however, often result in loss of activity and thus therapeutic usefulness. This is often the case with lower molecular weight peptides which have few attachment sites not associated with bioactivity. Many non-peptide therapeutics also lack a sufficient number of attachment sites to obtain the benefit of polymer modification.
One suggestion for overcoming the problems discussed above is to use longer, higher molecular weight polymers. These materials, however, are difficult to prepare and expensive to use. Further, they provide little improvement over more readily available polymers.
Another alternative suggested is to attach two strands of polymer via a triazine ring to amino groups of a protein. See, for example, Enzyme, 26, 49-53 (1981) and Proc. Soc. Exper. Biol. Med., 188, 364-9 (1988). Triazine, however, is a toxic substance which is difficult to reduce to acceptable levels after conjugation. In addition, triazine is a planar group and can only be double-polymer substituted. The planar structure rigidly locks the two polymer chains in place. This limits the benefits of polymer conjugation to about the same as that obtained by increasing polymer chain length. Thus, non-triazine-based activated polymers would offer substantial benefits to the art.
In the above-mentioned cases, however, the biologically active polymer conjugates were formed having substantially hydrolysis-resistant bonds (linkages) between the polymer and the parent biologically-active moiety. Thus, long-lasting conjugates which are of a rather permanent nature rather than prodrugs per se (where the parent molecule is eventually liberated in vivo were prepared.
In addition, over the years, several methods of preparing prodrugs have also been suggested. Prodrugs include chemical derivatives of a biologically-active parent compound which, upon administration, will eventually liberate the active parent compound in vivo. Use of prodrugs allows the artisan to modify the onset and/or duration of action of a biologically-active compound in vivo. Prodrugs are often biologically inert or substantially inactive forms of the parent or active compound. The rate of release of the active drug is influenced by several factors including the rate of hydrolysis of the linker which joins the parent biologically active compound to the prodrug carrier.
Prodrugs based on ester or phosphate linkages have been reported. In most cases, the particular type of ester linkage used to form the prodrug provides Txc2xd for hydrolysis of up to several days in aqueous environments. Although one would expect a prodrug to have been formed, most of the conjugate is eliminated prior to sufficient hydrolysis being achieved in vivo. It would therefore be preferable to provide prodrugs which have a linkage which allows more rapid hydrolysis of the polymer-drug linkage in vivo so as to generate the parent drug compound more rapidly.
It has also been surprisingly found that when only one or two polymers of less than 10,000 molecular weight (each) are conjugated to biologically-active compounds such as organic moieties, the resulting conjugates are often rapidly eliminated in vivo. In fact, such conjugates are often so rapidly cleared from the body that even if a substantially hydrolysis-prone ester linkage is used, not enough of the parent molecule is regenerated.
Even though previous prodrugs based on conjugates of a parent drug compound on a water soluble polymer have not been successful for a variety of reasons, including excessively slow hydrolysis of the linkage, work in this area has continued. There is still a need in improvements in polymer-based prodrugs and, in particular, ways of significantly increasing the payload of the polymer portion of the prodrug. The present invention addresses these shortcomings.
In one aspect of the invention, there are provided branched, substantially non-antigenic polymers corresponding to the formula:
(R)nLxe2x80x94Axe2x80x83xe2x80x83(I)
wherein (R) includes a water-soluble non-antigenic polymer;
(n)=2 or 3;
(L) is an aliphatic linking moiety covalently linked to each (R); and
(A) represents an activating functional group capable of undergoing nucleophilic substitution.
For example, (A) can be a group which is capable of bonding with biologically active nucleophiles or moieties capable of doing the same. In particularly preferred aspects of the invention, (R) includes a poly(alkylene oxide) PAO such as a poly(ethylene glycol) (hereinafter: PEG).
One preferred embodiment of the invention provides branched polymers containing a terminal carboxylic acid group which is useful in the formation of ester-based prodrugs. The branched polymers are of the formula:
(R)nLxe2x80x94COOHxe2x80x83xe2x80x83(Ia)
where (R), (n), and (L) are as defined above.
Another preferred embodiment of the invention includes branched polymers of the same formula set forth above, i.e.: (R)nL-A, except that (L) is selected from the group consisting of
where (a) is an integer of from about 1 to about 5;
X is O, NQ, S, SO or SO2; where Q is H, C1-8 alkyl, C1-4 branched alkyl, C1-8 substituted alkyl, aryl or aralkyl;
(m) is 0 or 1;
(p) is a positive integer, preferably from about 1 to about 6;
(R) and (n) are as defined above; and
(A) is as defined above, including COOH as set forth in Formula (Ia).
These umbrella-like branched polymers of the present invention (U-PAO""s or U-PEG""s) react with biologically active nucleophiles to form conjugates. The point of polymer attachment depends upon the functional group (A). For example, (A) can be a succinimidyl succinate or carbonate and react with epsilon amino lysines. Alternatively, (A) can be a carboxylic acid which is capable of reacting with hydroxyl groups found on biologically-active nucleophiles to form ester-linked prodrugs. The branched polymers can also be activated to link with any primary or secondary amino group, mercapto group, carboxylic acid group, reactive carbonyl group or the like found on biologically-active materials. Other groups are apparent to those of ordinary skill in the art.
Other aspects of the invention include conjugates containing biologically-active materials and one or more of the branched polymers described above as well as methods of their preparation. The biologically active materials include proteins, peptides, enzymes, medicinal chemicals or organic moieties whether synthesized or isolated from nature. The methods include contacting a biologically active material containing a nucleophile capable of undergoing a substitution reaction with a branched polymer described above under conditions sufficient to effect attachment while maintaining at least a portion of the biological activity.
The present invention also includes methods of treating various maladies and conditions. In this aspect, a mammal in need of treatment is administered an effective amount of a conjugate containing a biologically-active material such as a protein, enzyme or organic moiety and a branched polymer of the present invention.
One of the chief advantages of the present invention is that the branching of the polymers imparts an umbrella-like three-dimensional protective covering to the materials they are conjugated with. This contrasts with the string-like structure of conventional polymer conjugates. Moreover., the branching of the polymer chains from a common root allows dynamic, non-planar action in vivo. Thus, the branched polymers offer substantial benefits over straight-chained polymers of equivalent molecular weight.
A second advantage of the branched polymers is that they provide the benefits associated with attaching several strands of polymers to a bioeffecting material but require substantially fewer conjugation sites. The advantages of the branched polymers are particularly dramatic for therapeutic agents having few available attachment sites. All the desired properties of polymer conjugation are realized and loss of bioactivity is minimized.
1. POLYMER SUBSTITUENTS AND FORMULA (I) DEFINED
The activated branched polymers of the present invention are preferably prepared from poly(alkylene oxides) (PAO""s) that are water soluble at room temperatures. Within this group are alpha-substituted polyalkylene oxide derivatives such as methoxypoly (ethylene glycols) (mPEG) or other suitable alkyl substituted PAO derivatives such as those containing mono or bis terminal C1-C4 groups. Straight-chained non-antigenic polymers such as monomethyl PEG homopolymers including
are preferred. Alternative polyalkylene oxides such as other poly(ethylene glycol) homopolymers, other alkyl-poly(ethylene oxide) block copolymers, and copolymers of block copolymers of poly(alkylene oxides) are also useful.
The polymers of the present invention are represented by Formula (I):
(R)nL-A (I)
wherein:
(R) includes a water-soluble, substantially non-antigenic polymer;
(n)=2 or 3;
(L) is an aliphatic linking moiety covalently linked to each (R); and
(A) represents an activating functional group capable of undergoing nucleophilic substitution.
Each (R) can be a water-soluble, substantially non-antigenic polymer chain. When the polymer chains are PEG or mPEG, if, is preferred that each chain have a molecular weight of between about 200 and about 80,000 daltons and preferably between about 2,000 and about 42,000 daltons. Molecular weights of about 5,000 to about 20,000 daltons are most preferred.
Alternative polymeric substances include materials such as dextrans, polyvinyl pyrrolidones, polyacrylamides or other similar non-immunogenic polymers. Such polymers are also capable of being functionalized or activated for inclusion in the invention. The foregoing is merely illustrative and not intended to restrict the type of non-antigenic polymers suitable for use herein.
In another embodiment of the invention, (R) is a branched polymer for secondary and tertiary branching from a bioactive material. Bifunctional and hetero-bifunctional active polymer esters can also be used. The polymers of the present invention can also be copolymerized with bifunctional materials such as poly(alkylene glycol) diamines to form interpenetrating polymer networks suitable for use in permeable contact lenses, wound dressings, drug delivery devices and the like. The stearic limitations and water solubility of such branching will be readily recognized by one of ordinary skill in the art. Preferably, however, the molecular weight of multiple branched polymers should not exceed 80,000 daltons.
As shown in Formula I, 2 or 3 polymer chains, designated (R) herein, are joined to the aliphatic linking moiety (L). Suitable aliphatics include substituted alkyl diamines and triamines, lysine esters and malonic ester derivatives. The linking moieties are preferably non-planar, so that the polymer chains are not rigidly fixed. The linking moiety (L) is also the means for attaching the multiple polymer chains or xe2x80x9cbranchesxe2x80x9d to (A), the moiety through which the polymer attaches to bio-effecting materials.
(L) preferably includes a multiple-functionalized alkyl group containing up to 18, and more preferably, between 1-10 carbon atoms. A heteroatom such as nitrogen, oxygen or sulfur may be included within the alkyl chain. The alkyl chain may also be branched at a carbon or nitrogen atom. In another aspect of the invention, (L) is a single nitrogen atom.
(L) and each (R) are preferably joined by a reaction between nucleophilic functional groups on both (R) and (L). Each (R) is suitably functionalized to undergo nucleophilic substitution and bond with (L). Such functionalization of polymers is readily apparent to those of ordinary skill in the art.
A wide variety of linkages are contemplated between (R) and (L). Urethane (carbamate) linkages are preferred. The bond can be formed, for example, by reacting an amino group such as 1,3-diamino-2-propanol with methoxypolyethylene glycol succinimidyl carbonate described in U.S. Pat. No. 5,122,614, the disclosure of which is incorporated herein by reference. Amide linkages, which can be formed by reacting an amino-terminated non-antigenic polymer such as methoxy-polyethylene glycol-amine (mPEG amine) with an acyl chloride functional group.
Examples of other linkages between (R) and (L) include ether, amine, urea, and thio and thiol analogs thereof as well as the thio and thiol analogs of the above-discussed urethane and amide linkages. The linkages are formed by methods well understood by those of ordinary skill in the art. Other suitable linkages and their formation can be determined by reference to the above-cited U.S. Pat. No. 4,179,337.
The moiety (A) of Formula I represents groups that xe2x80x9cactivatexe2x80x9d the branched polymers of the present invention for conjugation with biologically active materials.
(A) can be a moiety selected from:
I. Functional groups capable of reacting with an amino group such as:
a) carbonates such as the p-nitrophenyl, or succinimidyl;
b) carbonyl imidazole;
c) azlactones;
d) cyclic imide thiones; or
e) isocyanates or isothiocyanates.
II. Functional groups capable of reacting with carboxylic acid groups and reactive carbonyl groups such as:
a) primary amines; or
b) hydrazine and hydrazide functional groups such as the acyl hydrazides, carbazates, semicarbamates, thiocarbazates, etc.
III. Functional groups capable of reacting with mercapto or sulfhydryl groups such as phenyl glyoxals; see, for example, U.S. Pat. No. 5,093,531, the disclosure of which is hereby incorporated by reference.
IV. Functional groups capable of reacting with hydroxyl groups such as (carboxylic) acids, such as in Formula (Ia) or other nucleophiles capable of reacting with an electrophilic center. A non-limiting list includes, for example, hydroxyl, amino, carboxyl, thiol groups, active methylene and the like.
The moiety (A) can also include a spacer moiety located proximal to the aliphatic linking moiety, (L). The spacer moiety may be a heteroalkyl, alkoxy, alkyl containing up to 18 carbon atoms or even an additional polymer chain. The spacer moieties can added using standard synthesis techniques. It is to be understood that those moieties selected for (A) can also react with other moieties besides biologically active nucleophiles.
One preferred embodiment of the invention provides branched polymers containing a terminal carboxylic acid group which is useful in the formation of ester-based prodrugs. The branched polymers are of the formula:
(R)nLxe2x80x94COOH (Ia)
where (R), (n), and (L) are as defined above.
Some particularly preferred compounds within this aspect of the invention include:
wherein:
(a) is an integer of from about 1 to about 5;
(m) is 0 or 1;
X is O, NQ, S, SO or SO2; where Q is, H, C1-8 alkyl, C1-8 branched alkyl, C1-8 substituted alkyl, aryl or aralkyl;
(p) is 0 or an integer from about 1 to about 6; and
R2 represents the corresponding spacer moiety R2, described below, after undergoing the substitution reaction which results in the addition of the terminal carboxylic acid group.
It will, of course, be readily apparent to those of ordinary skill that the mPEG shown above for illustrative purposes can be replaced by any polyalkylene oxide or other substantially non-antigenic polymer described herein.
Another preferred embodiment of the invention includes branched polymers of the same formula set forth above, i.e. (I) and (Ia): (R)nL-A, except that (L) is selected from the group consisting of
where (a), (m), (p) and X are as set forth above.
Some particularly preferred compounds within this aspect of the invention include:
wherein:
(a) is an integer of from about 1 to about 5;
(m) is 0 or 1;
(p) is a positive integer, preferably from about 1 to about 6; and
R2 is a spacer moiety selected form the group consisting of: polymers, xe2x80x94COxe2x80x94NHxe2x80x94 (CH2xe2x80x94)dX2, xe2x80x94COxe2x80x94NHxe2x80x94 (CH2xe2x80x94CH2xe2x80x94Oxe2x80x94)dX2, xe2x80x94COxe2x80x94NHxe2x80x94
and
where (d) is an integer between about 1 and about 18 inclusive and (X2) is H, OH, NH2 or COOH.
2. SYNTHESIS OF BRANCHED POLYMERS
The branched polymers (generally, U-PAO""s or U-PEG""s) are formed using conventional reaction techniques. For each polymer chain (R) attached, the linking compound (L) has a number of nucleophilic functional groups which correspond to (n), (i.e. 2 or 3). In one aspect, a succinimidyl carbonate active ester of the branched polymer is prepared by contacting a branched polymer subunit (R)nL, prepared as described above, with p-nitrophenyl chloroformate and thereafter with N-hydroxysuccinimide to form a succinimidyl carbonate. Alternatively, the hydroxy moiety can be reacted with bis-succinimidyl carbonate directly. The polymer subunit (R)nL will include hydroxyl, amino, carboxyl and thiol groups, and the like, as well as amino or methylene hydrogens so that it can be attached to (A).
The branched polymers can also be formed by reacting aliphatic linking compounds substituted with nucleophilic functional groups such as di- or tri-amino, mercapto alcohols or alkyl triols with an activated or functionalized polymer chain such as SC-PEG, PEG-NCO, PEG-NCS, SS-PEG, PEG-acids and acid derivatives. Such methods are preferred because functionalized polymer chains and suitable aliphatic lining groups are either commercially available or readily synthesized.
Other aspects of synthesis include reacting a polymer functionalized with a nucleophilic moiety such as PEG-alcohol, PEG-amine or PEG-mercaptan with bifunctional molecules such as malonic acid derivatives or glyoxalic acid derivatives.
For example, two moles of methoxy-poly(ethylene glycol) amine can be reacted with a substituted or unsubstituted malonyl chloride to form a compound of Formula (II):
Reaction with strong base converts the methylene linker into an anion that can be further functionalized. For example, the anion can be reacted with diethyloxalate to yield the corresponding ketoester.
Likewise, two moles of methoxy-poly(ethylene glycol) succinimidyl carbonate may be reacted with a 1,3 diamino 2-propanol to form a compound of Formula (III):
Similarly, two moles of mPEG-N-acyl-thiazolidine (hereinafter mPEG-FLAN) which can be prepared according to U.S. Pat. No. 5,349,001, the contents of which are incorporated herein by reference, can be reacted with a triamine such as diethylenetriamine to form a compound having the structure of Formula (IV):
Branched polymers (III) and (IV) can then be activated. One manner of activation of (III) includes first functionalizing with compounds capable of activating the hydroxyl group such as p-nitrophenyl chloroformate to form a reactive p-nitrophenyl carbonate. The resulting p-nitrophenyl carbonate polymer can be directly reacted with a biologically active nucleophile.
The p-nitrophenyl carbonate polymer can also serve as an intermediate. It can be reacted with a large excess of N-hydroxysuccinimide to form a succinimidyl carbonate-activated branched polymer. Other routes to succinimidyl carbonates are available and contemplated for use herein. Alternatively, a p-nitrophenyl carbonate polymer intermediate can be reacted with anhydrous hydrazine to form a carbazate branched polymer.
Branched polymer (III) can also be activated by reacting it with an alkyl haloacetate in the presence of a base to form an intermediate alkyl ester of the corresponding polymeric carboxylic acid and thereafter reacting the intermediate alkyl ester with an acid such as trifluoroacetic acid to form the corresponding polymeric compound containing a terminal carboxylic acid. Preferably, tertiary alkyl haloacetates are used. In particular, the carboxylic acid derivative is formed by:
i) contacting a branched polymer of the structure: (R)nLxe2x80x94A, wherein (R), (n), (L) and (A) are as defined herein, with an alkyl haloacetate in the presence of a base to form an alkyl ester of a branched non-antigenic polymer; and
ii) reacting the alkyl ester with an acid to form the branched polymer containing a reactive carboxylic acid thereon.
In carrying out the reaction, the molar ratio of the alkyl haloacetate to the branched polymer, i.e. polyalkylene oxide, is greater than 1:1. The reacting step ii) is carried out at a temperature of from about 0xc2x0 to about 50xc2x0 C. and preferably at a temperature of from about 20 to about 30xc2x0 C. Optionally, the reacting step ii) can be carried out in the presence of water. Preferably, tertiary alkyl haloacetates of the formula:
wherein:
X3 is chlorine, bromine or iodine; and
R10-12 are independently selected from the group consisting of C1-8 alkyls, C1-8 substituted alkyls or C1-8 branched alkyls and aryls are used.
Preferred tertiary alkyl haloacetates include tertiary butyl haloacetates such as t-butyl bromoacetate or t-butyl chloroacetate. Suitable bases include potassium t-butoxide or butyl lithium, sodium amide and sodium hydride. Suitable acids include trifluoroacetic acid or sulfuric, phosphoric and hydrochloric acids.
Branched polymer (IV) can be activated by reacting it with a hydroxy acid such as lactic acid or glycolic acid to form the hydroxy amide. Thereafter, the hydroxy amide is functionalized in the same manner discussed above for (III).
In another embodiment, two moles of methoxy-poly(ethylene glycol) acid or mPEG-FLAN can be reacted with 1,3-diamino-2-hydroxypropane to form a compound of formula (IIIa):
Similarly, two moles of mPEG acid or, preferably, mPEG-FLAN can be reacted with a triamine such as diethylenetriamine to form a compound having the structure of Formula (IVa):
(a) in this case is 2.
Branched polymer (IIIa) and (IVa) can then be activated in the same way as described above with regard to compounds (III) and (IV).
In the case where m is zero (i.e. the carbonyl group is absent) synthesis of the branched polymer can be formed with a triamine (i.e. diethylenetriamine) being reacted with two equivalents of an acylating agent such as succinimidyl carbonate-activated PEG (SC-PEG), so that the terminal amino groups are functionalized with the PEG. This intermediate which contains a secondary amine is then alkylated with ethyl bromoacetate or t-butyl bromoacetate to yield the branched polymer.
In the case where m is one (i.e. a carbonyl group is present) synthesis of the branched polymer can be formed in a similar fashion. The terminal amines are functionalized with an activated PEG such as SC-PEG. Then, the residual secondary amine is reacted with another acylating agent such as succinic anhydride under more forceful conditions so that the less reactive tertiary amine is acylated.
As will be readily appreciated, numerous variations and combinations of the reaction between the functionalized polymer chains and aliphatic linking compound can be utilized to form the compounds of the present invention. The foregoing reactions were disclosed to illustrate the present invention.
Branched polymers corresponding to Formulas (II), (III), (IIIa), (IV), (IVa) and the like, can also be extended with a spacer moiety, designated herein as R2, between the aliphatic linking moiety and the group capable of undergoing nucleophilic substitution. For example, the polymer of Formula (III) with a spacer moiety is represented by Formula (V):
Spacer moieties represented by (R2) include but are not limited to:
xe2x80x94COxe2x80x94NHxe2x80x94(CH2xe2x80x94)dX4
xe2x80x94COxe2x80x94NHxe2x80x94(CH2xe2x80x94CH2xe2x80x94Oxe2x80x94)dH

and the like, where (d) is an integer between 1 and 18 inclusive and (X4) is OH, NH2 or COOH. Depending upon the circumstances, an xe2x80x94H of an xe2x80x94OH group is attached to the end of the spacer moiety to form the terminal hydroxyl group. Thus, the spacer group is said to be proximal to L.
Synthesis of compounds corresponding to (V) include reacting the p-nitrophenyl carbonate or N-succinimidyl carbonate active esters of Formula (III) compounds with reagents such as
H2Nxe2x80x94(CH2xe2x80x94)dOH
H2Nxe2x80x94(CH2xe2x80x94CH2xe2x80x94Oxe2x80x94)dH,
aminophenols, or

The compounds of Formulas (IIIa) and (IVa) can also be converted into the corresponding R2 spacer-containing compounds in the same manner as that set forth above.
The attachment of spacer moieties to a branched polymer is described with reference to the polymer of Formula (II) for purposes of illustration, not limitation. Similar products would be obtained with any of the branched polymers disclosed by the present invention. For example, spacer moieties (R2) can be joined to linker moieties (L) substituted with groups other than hydroxyl groups. When the hydroxyl group is replaced by an amino group, or when the carbon substituted with hydroxyl groups is replaced by a secondary amine, (L) can be reacted with suitable reagents such as substituted isocyanates or isothiocyanates and the like. Like the aliphatic linking moieties described above, the terminal groups of the spacer moieties can be similarly functionalized to react with nucleophiles, i.e. attachment of a suitable (A) moiety, i.e. COOH or other xe2x80x9cactivated terminal groupxe2x80x9d.
After synthesis, the activated branched polymers can be purified by conventional methods and reacted with biologically active materials containing nucleophiles capable of bonding with the polymer while maintaining at least some of the activity associated with the material in unmodified form.
3. BIOLOGICALLY ACTIVE MATERIALS SUITABLE FOR CONJUGATION
The nucleophiles conjugated with the branched polymers are described as xe2x80x9cbiologically activexe2x80x9d. The term, however, is not limited to physiological or pharmacological activities. For example, some nucleophile conjugates such as those containing enzymes, are able to catalyze reactions in organic solvents. Likewise, some inventive polymer conjugates containing proteins such as concanavalin A, immunoglobulin and the like are also useful as laboratory diagnostics. A key feature of all of the conjugates is that at least some portion of the activity associated with the unmodified bio-active material is maintained.
The conjugates are biologically active and have numerous therapeutic applications. Mammals in need of treatment which includes a biologically active material can be treated by administering an effective amount of a polymer conjugate containing the desired bioactive material. For example, mammals in need of enzyme replacement therapy or blood factors can be given branched polymer conjugates containing the desired material.
Biologically active nucleophiles of interest of the present invention include, but are not limited to, proteins, peptides, polypeptides, enzymes, organic molecules of natural and synthetic origin such as medicinal chemicals and the like.
Enzymes of interest include carbohydrate-specific enzymes, proteolytic enzymes, oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases. Without being limited to particular enzymes, examples of enzymes of interest include asparaginase, arginase, arginine deaminase, adenosine deaminase, superoxide dismutase, endotoxinases, catalases, chymotrypsin, lipases, uricases, adenosine diphosphatase, tyrosinases and bilirubin oxidase. Carbohydrate-specific enzymes of interest include glucose oxidases, glucodases, galactosidases, glucocerebrosidases, glucouronidases, etc.
Proteins, polypeptides and peptides of interest include, but are not limited to, hemoglobin, both naturally occurring and recombinant mutant strains, serum proteins such as blood factors including Factors VII, VIII, and IX; immunoglobulins, cytokines such as interleukins, xcex1-, xcex2- and xcex3-interferons, colony stimulating factors including granulocyte colony stimulating factors, platelet derived growth factors and phospholipase-activating protein (PLAP). Other proteins of general biological or therapeutic interest include insulin, plant proteins such as lectins and ricins, tumor necrosis factors and related alleles, growth factors such as tissue growth factors, such as TGFxcex1""s or TGFxcex2""s and epidermal growth factors, hormones, somatomedins, erythropoietin, pigmentary hormones, hypothalamic releasing factors, antidiuretic hormones, prolactin, chorionic gonadotropin, follicle-stimulating hormone, thyroid-stimulating hormone, tissue plasminogen activator, and the like. Immunoglobulins of interest include IgG, IgE, IgM, IgA, IgD and fragments thereof.
Some proteins such as the interleukins, interferons and colony stimulating factors also exist in non-glycosylated form, usually as a result of using recombinant techniques. The non-glycosylated versions are also among the biologically active nucleophiles of the present invention.
The biologically active nucleophiles of the present invention also include any portion of a polypeptide demonstrating in vivo bioactivity. This includes amino acid sequences, antisense moieties and the like, antibody fragments, single chain binding antigens, see, for example U.S. Pat. No. 4,946,778, disclosure of which is incorporated herein by reference, binding molecules including fusions of antibodies or fragments, polyclonal antibodies, monoclonal antibodies, catalytic antibodies, nucleotides and oligonucleotides.
The proteins or portions thereof can be prepared or isolated by using techniques known to those of ordinary skill in the art such as tissue culture, extraction from animal sources, or by recombinant DNA methodologies. Transgenic sources of the proteins, polypeptides, amino acid sequences and the like are also contemplated. Such materials are obtained from transgenic animals, i.e., mice, pigs, cows, etc., wherein the proteins are expressed in milk, blood or tissues. Transgenic insects and baculovirus expression systems are also contemplated as sources. Moreover, mutant versions of proteins, such as mutant TNF""s and/or mutant interferons are also within the scope of the invention.
Other proteins of interest are allergen proteins such as ragweed, Antigen E, honeybee venom, mite allergen, and the like.
Useful biologically active nucleophiles are not limited to proteins and peptides. Essentially any biologically-active compound is included within the scope of the present invention. The present invention is particularly well-suited for compounds which have few or even a single nucleophilic attachment site for polymer conjugation such as medicinal chemicals whether isolated from nature or synthesized. Chemotherapeutic molecules such as pharmaceutical chemicals i.e. anti-tumor agents such as paclitaxel, taxotere, related taxoteres, taxoid molecules, camptothecin, podophyllotoxin, anthracyclines, methotrexates, etc. cardiovascular agents, anti-neoplastics, anti-infectives, anti-anxiety agents, gastrointestinal agents, central nervous system-activating agents, analgesics, fertility or contraceptive agents, anti-inflammatory agents, steroidal agents, anti-urecemic agents, cardiovascular agents, vasodilating agents, vasoconstricting agents and the like.
The foregoing is illustrative of the biologically active nucleophiles which are suitable for conjugation with the polymers of the invention. It is to be understood that those biologically active materials not specifically mentioned but having suitable nucleophilic groups are also intended and are within the scope of the present invention.
4. SYNTHESIS OF BIOLOGICALLY ACTIVE CONJUGATES
One or more of the activated branched polymers can be attached to a biologically active nucleophile by standard chemical reactions. The conjugate is represented by the formula:
[(R)nLxe2x80x94A1]z-(nucleophile)xe2x80x83xe2x80x83(VI)
wherein (R) is a water-soluble substantially non-antigenic polymer; n=2 (L) is an aliphatic linking moiety; (A1) represents a linkage between (L) and the nucleophile and (z) is an integer xe2x89xa71 representing the number of polymers conjugated to the biologically active nucleophile. The upper limit for (z) will be determined by the number of available nucleophilic attachment sites and the degree of polymer attachment sought by the artisan. The degree of conjugation can be modified by varying the reaction stoichiometry using well-known techniques. More than one polymer conjugated to the nucleophile can be obtained by reacting a stoichiometric excess of the activated polymer with the nucleophile.
The biologically active nucleophiles can be reacted with the activated branched polymers in an aqueous reaction medium which can be buffered, depending upon the pH requirements of the nucleophile. The optimum pH for the reaction is generally between about 6.5 and about 8.0 and preferably about 7.4 for proteinaceous/polypeptide materials. Organic/chemotherapeutic moieties can be reacted in non-aqueous systems. The optimum reaction conditions for the nucleophile""s stability, reaction efficiency, etc. is within level of ordinary skill in the art. The preferred temperature range is between 4xc2x0 C. and 37xc2x0 C. The temperature of the reaction medium cannot exceed the temperature at which the nucleophile may denature or decompose. It is preferred that the nucleophile be reacted with an excess of the activated branched polymer. Following the reaction, the conjugate is recovered and purified such as by diafiltration, column chromatography, combinations thereof, or the like.
It can be readily appreciated that the activated branched non-antigenic polymers of the present invention are a new and useful tool in the conjugation of biologically active materials, especially when they lack a sufficient number of suitable polymer attachment sites.

Non-antigenic branched polymer conjugates


Leg twist in jeans made of twill fabrics may be avoided by skewing the fabric clockwise or counterclockwise depending on the twill direction before making the garment so that when the garment is laundered the positions of the warp and filling yarns will remain unchanged with respect to each other. For denim an 8% skew based on fabric width introduced in manufacturing the denim gives straight seams throughout the life of the garment.

Leg twist is a serious problem in the manufacture of jeans, giving the appearance of a rotation of the legs in the opposite direction of the twill of the fabric after laundering. This invention relates to the avoidance of leg twist caused by unstabilized twill fabrics, usually medium to heavy weight cotton fabrics, used for slacks and jeans. Leg twist is believed to be the result of directional yarn stresses which are inherent in regular twill weave fabrics and thus introduced at the time of fabric construction and enduring until laundering, at which time relaxation of those yarn stresses result in a change of the angular relationship between warp and filling yarns, causing the legs to appear twisted. In certain instances, stresses are introduced into garments by sewing which also gives the leg "twist" appearance, but sewing stresses are outside the scope of this invention, which relates only to leg twist caused by fabric construction. Stabilized twill fabrics, such as permanent press finished, are usually outside the scope of this invention, because the relationship between yarns is chemically fixed. On the other hand, shrinkage stabilization (i.e. Sanforizing) is, of course, included since most cotton twill jeans and slacks are pre-shrunk. The described leg twist does not show on garments at the time of purchase, but only after the garments have been laundered. Leg twist appears after the first laundering and usually grows progressively worse with increased number of launderings. The volume of jeans manufactured from medium to heavy weight cotton twill fabrics, particularly from blue denim, has increased in recent years because of changing apparel buying habits which have created an unprecedented demand for jeans. As a result, the long-standing problem of leg twist, further accentuated by the flared leg bottoms which have been in fashion for several years, has become a substantial problem. It is estimated that the returns of jeans to manufacturers because of leg twist numbers in excess of one hundred thousand annually and that the number of dissatisfied customers who do not return jeans having leg twist exceeds that number by a factor of at least six. Some manufacturers have resorted to broken twill weaves in order to avoid the problem of leg twist, but there is a very strong demand for jeans made of regular cotton twill fabrics.
It has been known that fabrics tend to skew during piece dyeing, preparation and finishing. For this purpose, devices such as fabric or weft straighteners have been developed which automatically sense any deviation from the perpendicular relationship between warp and filling yarns and automatically correct such deviation by differential straightening. In this way, registry of prints on fabrics, for example, can be maintained. However, such devices are intended to reduce deviation from the perpendicular state and are not intended to purposefully introduce skew into the fabrics. Commonly, fabric straighteners are used for knit fabrics which are then heat-set to give permanent straightness. Heretofore, any introduction of skew or deviation from the perpendicular relationship between warp and filling yarns in jean weight fabrics has been scrupulously avoided.

Method of skewing twill fabric to avoid leg twist


The present invention relates to a gelled cosmetic emulsion comprising an oil phase, an aqueous phase and a gelling system which contains at least one non-siloxane based polyamide in a sufficient amount to gel the emulsion. The polyamide can have an ester, acid, or amine terminal end group. The emulsion is stabilized with an alkylene oxide containing emulsion stabilizer. The emulsions of the present invention are substantially transparent and when colorants are added the color is especially bright and clear. The emulsions are used in lipstick and mascara products as well as other gel and stick products.

The invention relates to a cosmetic and personal care gel product that is gelled using a polyamide as a gelling agent in the oil phase. More specifically, the invention relates to a stable emulsion based compositions comprising a polyamide gelling agent in the oil phase.
Many gelled cosmetic emulsions rely on gellants, waxes, fillers, heavy oils, and plasticizers for developing the structure to make a gel or stick composition. The structure built by these agents and materials give the product a balance of rigidity and firmness depending on the desired product. For example, the structure of lipstick is traditionally formed by a blend of wax and oil. However, these adjuvants, particularly waxes, have a disadvantage in that they contribute to opacity which diminishes the color of the pigment. The product therefore, has a dull, lackluster and pale appearance. To overcome this problem, enhanced amounts of pigment are added to the composition. Another drawback to the addition of wax is that it adheres poorly to the skin and compromises the longevity of wear of the product. For example, many commonly used cosmetic products, such as foundation, concealer, eyeliner, and lipstick, which contain these materials are subject to fading, smudging, and flaking. Such products also have a matte appearance that is not always desirable. In addition, other adjuvants such as heavy oils can feel uncomfortable on the skin and have a distinct oily feel that may also be unpleasant. Therefore, to address these issues, alternative gelling agents have been sought and specific polyamides have been used to gel cosmetic products.
The use of polyamides in cosmetic products has been known. For example, polyamide resins have been used in an anhydrous lipstick as disclosed in U.S. Pat. No. 3,148,125. The method of making polyamides is disclosed in, for example, U.S. Pat. No. 2,450,940. The polyamide resin has also been used in a deodorant or antiperspirant gel or stick as disclosed in U.S. Pat. Nos. 4,275,054 and 5,500,209 because of its odor absorbing properties. None of these references, however, discloses an emulsion gelled with the non-siloxane based polyamide in combination with an ethylene oxide containing emulsion stabilizer. The stick, soft gel, or clear gel compositions disclosed in, for example, U.S. Pat. Nos. 6,051,216, 5,603,925, and 5,998,570 and European Patent Application Nos. EP 1 068 855 and EP 1 068 856 are unstable emulsions, single phase compositions, or use a siloxane based polyamide. The siloxane polyamides have been developed because of their alleged ability to, in addition to gel the composition, provide a less tacky composition. However, the siloxane based polyamides are not compatible with a wide variety of oils, for example, hydrocarbon oils, and because they are less tacky, their adhesion properties are significantly impaired, making them less desirable in products that require minimally an initial phase of adhesion during the application of the product to the skin or hair. Therefore. it is desirable to use other polyamides in cosmetic emulsion systems because products such as mascara, for example, need a certain degree of tackiness when being applied but afterwards, upon drying the tackiness of the mascara needs to transition to a comfortable feel on the lashes. Until now, it has not been known to fine-tune the tacky nature of a cosmetic dual phase product containing the polyamide resin as a gelling agent. The compositions heretofore have either been too tacky or not tacky enough for products that need to exhibit varying degrees of tackiness over time and during their use. Thus, the emulsions of the present invention gelled with a non-siloxane polyamide has heretofore not been known. A need for a stable cosmetic emulsion gelled by a polyamide resin system that adheres to the skin and functions in a variety of cosmetic emulsion systems still remains. The emulsion system of the present invention is also desirable because it allows water-soluble ingredients to be incorporated into the product containing the emulsion.
The invention relates to gelled cosmetic compositions, and specifically, oil-in-water or water-in-oil emulsions, which comprises at least one alkylene oxide containing emulsion stabilizer and at least one non-siloxane based polyamide resin. The prepared emulsions, while they are not themselves clear, are substantially transparent after application to the skin. Use of the polyamide resin as a gelling agent per se is not new, however, its incorporation into the color compositions of the present invention containing the C1-5 alkylene oxide, for example, ethylene oxide or propylene oxide, as an emulsion stabilizer is surprising. The cosmetic emulsions of the present invention also comprise a color component present in an amount greater than about 2.0 percent by weight of the composition. The ability to gel a color cosmetic emulsion with the polyamide resin as the primary gelling agent is particularly challenging because the polyamide is very polar and emulsions containing large quantities of polyamide tend to be tacky and are difficult to stabilize in the presence of colorants.
The present invention also includes methods of making the emulsion systems of the present invention which can include multiple emulsion systems. The emulsion products are especially transparent and transfer resistant when they are applied to the skin and allowed to dry. The compositions containing these emulsions have an enhanced brightness and clarity with respect to their color on the skin after application thereon due to the transparent film that adheres to the skin without being tacky. The emulsion systems of the present invention dry faster than other polyamide containing systems, and are long wearing even after the water evaporates. In addition, gels and sticks made with the emulsion system of the present invention are less brittle, experience a substantial lack of syneresis, and have a creamier texture because the three-dimensional structure formed by the polyamide resin is interrupted partially by the water phase.
The gelling system of the present invention is at least one non-siloxane based polyamide resin and at least one C1-5 alkylene oxide containing emulsion stabilizer. The polyamide resin as used herein is defined to be a polymer having recurring units of amide groups as an integral part of the main chain of the polymer and a terminal end group of acid, amine, or ester. The polyamide gelling agent can be used to produce a soft gel or a stick composition in an emulsified system. Therefore, it is preferable that the polyamide resin not be extensively cross-linked by hydrogen bonds. The polyamides are characterized as thermoplastics as opposed to thermosets. Based on complex fatty acids, esters, and amines, the polyamides used in the present invention are water insoluble. The polyamide is available in a solid form of 100 percent polyamide or as a percentage of polyamide in mineral oil, usually about 80 percent. Examples of commercially available polyamides which are useful in the present invention are Versamid 1655, by Cognis (formerly Henkel Corporation), Ambler, Pa. which is prepared from dimers of C18 unsaturated fatty acids which are partially hydrogenated, azelaic acid (nonanedioic acid), ethylene diamine, hexamethylene diamine and stearic acid, Unirez and Uniclear, a series of polyamides from Arizona Chemicals Corporation, Jacksonville, Fla. or Elvamide from DuPont, Del. a terpolymer of nylon 6, nylon 66, and nylon 610. Additional polyamides are disclosed in U.S. Pat. Nos. 4,820,765, 5,719,255, 5,807,968, 6,111,055, and 6,054,517, the contents of which are incorporated herein by reference. These references fail to recognize the ability to make a stable emulsion product, and thus, fail to recognize the benefits of a water containing cosmetic emulsion incorporating a polyamide gelling agent and an C1-5 alkylene oxide containing surfactant. For example, U.S. Pat. No. 5,783,657 is an anhydrous system, and U.S. Pat. No. 5,998,570 discloses that water is preferably removed when forming the polyamide, and compositions comprise a nonaqueous liquid as solvent, preferably a low-polarity liquid.
The water phase of the cosmetic emulsion of the present invention comprises about 0.05 to 90.0 percent, and preferably 1.0 to 70.0 percent by weight of the emulsions. While the water phase is primarily water, it can take the form of a variety of aqueous solutions such as rose water, tea, and the like. Therefore, the water phase is well suited to deliver water-soluble actives and other water dispersible agents, such as for example, film-formers, surfactants, and emollients. The non-aqueous phase can include any type of cosmetically acceptable volatile or non-volatile oil including oily esters depending on the application of the product and the degree of gelling desired. Examples include, but are not limited to, hydrocarbon oil such as isododecane, silicone oils such as cyclomethicone, polyorganosiloxanes such as phenyl-methicones and dimethicones, castor oil, and hydrogenated vegetable oil. Preferably, in a mascara, the oil is volatile, such as for example, a volatile hydrocarbon oil or silicone oil; while a lipstick is a mixture of both volatile and non-volatile oils and the amounts of each depends on the type of lipstick desired. Suitable non-volatile hydrocarbons include, but are not limited, to isoparaffins, squalane, or petrolatum, or mixtures thereof. Regardless of the amount of volatile and/or non-volatile oil, the entire oil phase is present in an amount of about 5 to about 95 percent, preferably 10 to 80 percent by weight of the composition, and more preferably about 10 to 40 percent.
The emulsions of the present invention are prepared by adding a gelling sufficient amount of the polyamide resin to the oil phase. The amount of polyamide resin used in the present invention is from about 1 to about 90 percent, preferably about 2 to 40 percent by weight of the composition. The amount of polyamide is a xe2x80x9cgelling sufficient amountxe2x80x9d and as used herein means an amount of polyamide in the oil phase to bring about an increase in the viscosity of the emulsion; preferably the viscosity increases by 25 percent, more preferably by 50 percent, and most preferably by 75 percent. This increase in viscosity is sufficient to form a thickened gel or form a solid having the hardness of a stick as the thickness of gels and sticks are known in the art. At lower levels, the polyamide aids in forming a gel, whereas, higher levels are used to make stick products. Although it is difficult to quantitatively distinguish between a cosmetic gel and stick, a gel is, in general, more viscous than a liquid; but, it is not as rigid or self-supporting as a stick. It is accepted by one of ordinary, skill in the art that a gel maintains a certain degree of deformity, whereas, the stick is free-standing and is substantially rigid.
Another component of the present invention is the C1-5 alkylene oxide containing emulsion stabilizer. Preferably, the emulsion stabilizer is an ethylene oxide or propylene oxide. It is surprisingly discovered with the present invention that a stable emulsion comprising the polyamide resin as the gelling agent can be achieved. Although, it is known to gel alcoholic based systems and oil based systems with the polyamide resin, until now, these systems have primarily been single phase. In particular, stable dual phase compositions, and especially, stable cosmetic emulsions, have not been known to contain a non-siloxane based polyamide gelling agent as they experience stability problems. The non-siloxane based polyamides arc known to be tacky. Therefore, their use is limited and most appropriate for coatings, paints, inks, epoxies, adhesives and the like. Their use in cosmetics has also been limited primarily to single phase systems such as anhydrous lipsticks and deodorants. However, the ability to formulate these types of cosmetics is quite different than the challenges presented by formulating a cosmetic emulsion, especially a stable emulsion in a color cosmetic.
The method of preparing the emulsions of the present invention entails basic steps known in the art for preparing emulsions. The non-siloxane based polyamide and the other ingredients in the oil phase may be prepared separately but arc combined or added to the oil phase before combining with the aqueous phase to make the emulsion. The present emulsions, containing the gelling system, can be prepared with the polyamide as the primary gelling agent in the gelling system or with other naturally derived or synthetic gellants or thickening agents, known and commonly used by one skilled in the art, such as for example, cetyl dimethicone copolyol, acrylates copolymer, dextrin fatty acid esters, carbopols, dibenzyl monosorbitol acetal, polyethylene wax, beeswax. carnauba wax, candilla wax, bayberry wax, rice wax, acylglutamic acid diamide, esters, fatty alcohols, and the like can be used in the oil phase of the present invention. Preferably, however, the compositions of the present invention are wax-free.
Surprisingly, it has been found that the presence of an ethylene oxide containing surfactant stabilizes the emulsion system containing the polyamide as the gelling agent. The ethylene oxide containing surfactant is known to be temperature sensitive, and therefore, when used in emulsions, experiences stability problems. Considering the difficulty of formulating a cosmetic emulsion, and in addition, the difficulty of incorporating the non-siloxane polyamide gelling agent in the emulsion, it is surprising that greater stability is achieved using the ethylene oxide containing emulsifier. While not wishing to be bound to any particular theory, it is believed that stability and enhanced gelling is achieved with the ethylene oxide containing emulsifier because it is capable of hydrogen bonding with the polyamide gelling agent. The emulsion stabilizer can be a single surfactant or a combination of surfactants. The emulsion stabilizers aid in rendering the polyamide resin compatible in the dual phase system, and enhance not only the stability of the emulsion containing the non-siloxane based polyamide resin as the gelling agent, but may also affect the gelling activity of the polyamide resin. Because the polyamide resin is water-insoluble when used as a gelling agent in the emulsion, stability problems are known to arise. In particular, agglomeration occurs or the phases separate in a short time, for example, in about few hours to about a few months. However, the present invention has discovered that this problem can be remedied with the emulsion stabilizer which can be present in the oil phase, the water phase, or both. As a result, the polyamide resin is rendered compatible in the emulsion stabilizer at room temperature and/or at elevated temperature. In addition, the emulsion is stable for about 6 months, preferably about 1 year, and more preferably about two years as measured by accelerated stability testing methods, known to one of ordinary skill in the art.
More preferably, the emulsion stabilizer of the present invention is primarily ethylene oxide containing surfactants, ethoxylated alcohols, and emulsifiers such as polyethlyene glycol esters. Specifically, the emulsion stabilizer can be cetyl dimethicone copolyol/polyglyceryl-4 isostearate/hexyl laurate, PEG-30 dipolyhydroxystearate, sorbitan tristearate, glyceryl stearate/PEG-100 stearate, glyceryl olivate, polysorbate 20, stearic acid, or laureth-7. Examples of solvents, include but are not limited to, emollients such as low polarity liquid emollients, straight chain and branched fatty alcohols, cetyl alcohol and isocetyl alcohol, monohydric or polyhydric alcohols, such as propylene glycol and dipropylene glycol, fatty acid esters, such as cetyl acetate/acetylated lanolin alcohol.
In yet another embodiment, the emulsion is stabilized by the addition of nitrogen containing soap-based emulsifiers, or alkanolamides of fatty acids, preferably, lauramide MEA or stearamide MEA, and derivatives thereof The lipstick containing, for example, lauramide MEA (monoethanolamine), is particularly effective in providing stability against the development of syneresis even when the lipstick is in the form of a water-in-oil emulsion.
Other features of the emulsions of the present invention include their substantial transparency when applied to the skin, good adherance to the skin without being tacky, and their substantial transfer resistance. The emulsions can be wax-free because the need to build structure with large amounts of wax is eliminated by the presence of the polyamide gelling agent. The use of the polyamide gelling agent in the presence of the water phase of an emulsion system is an improvement over traditional wax-based emulsions because wax forms an opaque oil phasc (i.e., when light scatters off of the wax microstructure). The opaque oil phase renders the color less brilliant because it interferes with the true appearance of the color even when applied to the skin. Further, wax has poor adhesion properties to the skin. Therefore, it is not long wearing. Although it is widely used in mascara, lipstick, and other products, the presence of wax can cause these products to transfer easily from the skin to other unwanted substrates (e.g., clothes, cups), the color fades quickly, and smudging and flaking are common problems as well. However, the polyamide gelled emulsions of the present invention adhere well to the skin. Strong adherance to the keratinous substrate is believed to be by hydrogen bonds between the polyamide and the keratin. The surprising benefit of the present invention is the ability to achieve opposing properties of adherance to the skin without a tacky feeling to the emulsion product. It is commonly found that measures taken to increase the adhesiveness of a composition result in a corresponding increase in the tackiness of the composition. However, the emulsions of the present invention overcome this mutual exclusivity and have both a pleasant creamy feel and good adherance to the skin.
In addition, to gelling a stable emulsion, the polyamide functions to maximize the color integrity because the emulsion is substantially transparent or semi-transparent when applied and allowed to dry on the skin. As used herein, xe2x80x9csubstantially transparentxe2x80x9d means that greater than 75 percent light can be transmitted through the oil phase; preferably, 80 percent; and more preferably, 90 percent. Thus, the term xe2x80x9ctransparencyxe2x80x9d as employed herein refers to invention cosmetic stick products which have translucent or transparent light transmitting properties, and refers to a clear body which has the property of transmitting light without appreciable scattering, so that objects beyond are entirely visible. The term xe2x80x9ctranslucentxe2x80x9d refers to a body which is partly transparent. The body admits and diffuses light, so that objects beyond are visible but cannot be clearly distinguished. The term xe2x80x9copaquexe2x80x9d refers to a body which is impervious to visible light. An opaque body lacks any degree of transparency.
The cosmetic emulsions of the present invention also include a colorant component comprising one or more colorants. The term xe2x80x9ccolorantxe2x80x9d as used herein includes pigments, dyes, stains, colorants, combinations thereof, and the like. Any cosmetically acceptable colorant can be used in the emulsions of the present invention. The color of the product after addition of the colorant is intense and bright upon application to the skin. Suitable organic pigments can be, for example, natural pigments, monomeric and polymeric synthetic pigments, or combinations thereof. Exemplary organic pigments include, but are not limited to, phthalocyanine blue and green pigments and azo-type red pigments such as naphthol red pigment. Other suitable aromatic pigment compounds include, but are not limited to, azo, triphenyl methane, indigo, anthraquinone, and xanthine dyes which are referred to as DandC, and FDandC pigments, such as for example, FDandC blue No. 1, FDandC green No. 5, FDandC red No. 40, and FDandC yellow No. 5. Also useful are lakes which are pigments formed by the precipitation and absorption of organic dyes in an insoluble base, such as alumina, barium, or calcium hydrates. Particularly preferred lakes are primary FDandC or DandC Lakes and blends thereof Colorant concentrations will vary depending upon the desired color or tint of the cosmetic product, but the colorant component generally will be greater than 2.0 percent, and preferably, greater than 5.0 percent by weight of the total composition.
The colorant can also be an inorganic pigment. The inorganic pigment is present in low amounts and preferably, the inorganic pigment has a small particle size, for example, a submicron particle size that will disperse and permit the cosmetic product to maintain a clear appearance. Examples of inorganic pigments include, but are not limited to, iron oxides (yellow, red, brown or black), ultramarines, chromium hydroxide green, chromium oxide, titanium dioxide (white), ferric ferrocyanide, ferric ammonium ferrocyanide, and mixtures thereof. The pigments can be ground by, for example, a rolling mill, or alternatively, the pigments can be purchased pre-ground in a blend containing, for example, water, polysaccharides, and black iron oxide. The ability to incorporate dyes, pigments and colorants is challenging in an emulsion system, especially one that contains the non-siloxane based polyamide as the gelling agent, and the ethylene oxide containing emulsion stabilizer. However, surprisingly, the color of the cosmetic emulsions of the present invention, after application to the skin, provides maximum color impact. The color is deep, brilliant and crisp.
The active ingredients incorporated in the emulsions of the present invention having a polyamide as the gelling agent preferably do not include antiperspirant actives especially those that are acidic metal salts. Examples of actives that can be used in the present invention include, but are not limited to, sunscreen actives, whitening agents, such as for example, antioxidants, antimicrobials, analgesics, anesthetics, anti-acne agents, antidermatitis agents, antipruritic agents, anti-inflammatory agents, antihyperkeratolytic agents, anti-dry skin agents, antipsoriatic agents, antiseborrheic agents, antiaging agents, antiwrinkle agents, self-tanning agents, wound-healing agents, corticosteroids, or hormones. The incorporation of the active in the formulation is determined by its solubility and/or stability in combination with non-siloxane polyamide gelled emulsions of the present invention. The term xe2x80x9csunscreenxe2x80x9d as used herein refers to any material which is capable of protecting skin from ultraviolet radiation having a wavelength of from about 280 to about 400 nm, by effectively absorbing such radiation, and/or reflecting or scattering such radiation away from the surface of skin. Examples of sunscreens with which the compositions of the present invention can be combined in this context are titanium dioxide, zinc oxide, benzophenones, octyl dimethyl PABA, amyldimethyl PABA, octyl methoxycinnamate, 2-ethoxy p-methoxycinnamate, oxybenzone, homosalate, phenyl. salicylate, avobenzene, glyceryl p-aminobenzoate, ethyl-p-glycosylimido benzoate and the like. In a formulation, the sunscreen agent is used in the amounts normally used for that agent. Preferably, the active is non-acidic. The selection of the mode of delivery for additional active ingredients, however, is limited to the mode of delivery chosen for the compositions.
The cosmetic product can be, but is not limited to, a lipstick, lip gloss or other lip product, a solid, or gel fragrance or perfume product, cleanser, toner, an eye product, such as a mascara, eyeliner or an eye gel, compact emulsion foundation, concealer, moisturizing skin lotion or cream, hair stick or gel, and any other makeup, or skin or sun care product that is in a gel or stick form. In a preferred embodiment, the product is a mascara or lipstick product. The base of the lipstick or mascara has sufficient clarity such that the color is bright and luminous, i.e., they are transparent, semi-transparent, or transluscent. The products of the present invention are long wearing, non-smudging, and non-flaking.
Further, the clear cosmetic product can contain other optional components as long as they do not interfere with the gelling properties of the polyamide. Examples include, but are not limited to, one or more preservatives such as, for example, propyl paraben, butyl paraben, mixtures thereof, or isoforms thereof, as well as butyl hydroxy toluene or butyl hydroxy anisol (BHT or BHA); fragrances (such as pinene); flavoring agents; waterproofing agents (such as PVP/eicosene copolymer); surfactants, such as silicone copolyols or fatty acid glycerol esters. and oil-soluble actives, such as tocopherol and its derivatives or retinol and its derivatives; and the like.

Stable cosmetic emulsion with polyamide gelling agent