Hydrophilic ampholytic polymer

Details Hydrophilic ampholytic polymer Hydrophilic ampholytic polymer

1998-12-29

2002-03-26

Page, Thurman K. (Department: 1615)

Drug, bio-affecting and body treating compositions

Live hair or scalp treating compositions

Polymer containing

C424S070120, C424S070130, C424S070140, C424S070220, C424S070240, C424S070270, C424S070310, C424S078080, C424S078100, C424S401000, C424S049000, C008S115600, C427S385500, C526S318420, C526S318440, C526S318500

Reexamination Certificate

active

06361768

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention is directed to a novel, hydrophilic, ampholytic polymer. Hydrophilic polymers readily associate with, have an affinity for, and dissolve in water. Ampholytic polymer(s), or polyampholyte(s), are polymer(s) having both cationic and anionic groups. The polymers of the present invention have utility as rheology modifiers in cationic and low pH (acidic) systems, as bioadhesives, as agents in the removal of bile salts and for enzyme inhibition, and as phosphate binding agents.
Ampholytic polymers are known. For example, U.S. Pat. Nos. 5,286,827; 5,216,098; 5,130,391; 5,116,921; and 5,075,399 teach superabsorbent crosslinked ampholytic ion pair copolymers, which are in powder form for incorporation into baby diapers. The ampholytic nature of the polymer facilitates the absorption of urine.
Polymers which are used as rheology modifiers or thickeners include non-ionic, cationic, anionic, and associative type thickeners. Non-ionic polymers include, for example, naturally occurring and chemically modified gums. Cationic polymers tend to be nonionic polymers, such as the natural gums which have been quaternized to make them compatible with cationic systems, although synthetic polymers are known, such as U.S. Pat. Nos 5,603,926 (Matsumoto et al) and 5,608,021(Uchiyama et al), which teach polymers from acrylic monomers having amino groups, and U.S. Pat. No. 5,321,110 (J. S. Shih), which teaches a vinyl pyrrolidone based polymer that includes an acrylic monomer having an amino group, which is quaternized to make it cationic. Anionic polymers, or polyelectrolytes include polycarboxylic acids, such as polyacrylic acid and the like. Associative polymer thickeners include hydrophobically-modified variations of non-ionic and ionic polymers, which function by “self-association” when dissolved in aqueous systems.
Unfortunately, however, the aforementioned conventional water-soluble polymers suffer from many serious deficiencies or limitations in actual use. For example, polymers are often added to personal care, medical, pharmaceutical, and household products to modify, the physical form, function, aesthetics and rheology properties of the formulations so that the product is delivered in a convenient form for application by the end user. Shampoos, for example, are theologically modified to allow a portion of the formulation to be readily poured from a container and yet be retained in the palm of the user's hand without flowing further. But, their use may lead to or be impeded by formulation problems, such as unfavorable interactions with other ingredients of the formulations. Commercial hair care and personal care formulations, in particular, often contain cationic and amphoteric surfactants, as well as salts, other polymers, non-aqueous solvents, oils, colorants, peroxides, acids, and bases. Hair conditioning compositions, for example, frequently include cationic surfactants as conditioning agents for improving conditioning and detangling of the hair. See, for example, U.S. Pat. No. 5,100,657 which discloses quaternary ammonium-containing cationic surfactants, such as dialkyldimethylammonium chlorides and salts of fatty amines. The interaction of the thickening polymer with these formulation ingredients results in substantial viscosity reduction, formation of insoluble complexes or produce “stringy” or viscous rheology. The natural cellulosic gums, even if modified to make them cationic thickeners, still tend to be unacceptable in terms of their rheology, which will include stringy, and elastic rheologies, which are esthetically and functionally undesirable in a final formulation.
In addition, cations, from, e.g., cationic and amphoteric surfactants, are commonly employed in the formulations of cosmetic, personal care, household, textiles paper coating and printing, pharmaceutical and other products such as shampoos, conditioners, hair gels, mousses, hand cleaning soaps, oral delivery compositions such as syrups, as carriers for drugs in tablet form, in dental products, such as toothpaste and the like. A problem is that surfactants in a system may tend to disrupt the thickening mechanism, so that the thickeners tend to lose their viscosity in the presence of the surfactants typically used in cosmetic compositions. Anionic polymeric thickeners which are known to thicken and maintain the viscosity of cosmetic, and other formulations in an efficient and aesthetic manner, do not maintain their viscosity in the presence of cationic surfactants. Some nonionic thickeners can maintain the viscosity of cationic or amphoteric surfactant-containing formulations, however they have the problem that they produce elastic or “stringy” formulations which tend to flow as a single mass and are aesthetically unacceptable.
Hydrophilic polymers have been used for many years in bioadhesion systems in dentistry, orthopaedics, drug delivery, and surgical applications. The term “bioadhesion” has been used to describe phenomena related to the ability of some synthetic and biological macromolecules and hydrocolloids to adhere to biological tissues. For drug delivery, natural and synthetic bioadhesive polymers of different ionic charge (neutral, anionic, or cationic) are selected for their bioadhesive properties. The pH of the body varies throughout the digestive system. The stomach, for example, has a pH of around 1 to 2, whereas the intestinal tract has a pH in the range of 5 to 8. By selecting polymers with suitable ionic charge, the site of adsorption can be varied according to the pH. More recently, there has also been a significant interest in the use of hydrophilic polymers as bioadhesive materials in other areas, such as soft tissue-based artificial replacement and controlled release systems for local release of bioactive agents. Such applications include systems for release of drugs in the buccal or nasal cavities and for intestinal or rectal administration. For example, Blanco-Fuente et al. discloses the bioadhesive properties of natural cellulosic and crosslinked acrylic acid polymers. (Int. J. Pharm. 138, pp. 103-112 (1996)). The bioadhesive properties of poly N-vinylpyrrolidone (PNVP), and poly hydroxyethylmethacrylate (PHEMA) have been reported by Robert et al. (Acta Phar. Tehnol., 34 (2) pp. 95-98 (1988)). Natural cationic materials, such as chitosan have also been found to exhibit good bioadhesive properties. However, because such polymers are sometimes incompatible with certain active agents, such as medicines, which are to be delivered, there exists a need for polymers having bioadhesive properties which will provide that compatibility and perform at the desired pH levels.
In some cases, hydrophilic polymer systems have been used as therapeutic agents themselves. Burt et al. (J. Pharm. Sci. 76 (5), pp. 379-383 (1987)) discloses the use of an anion-exchange resin for binding phosphate in the blood. Phosphorus is present in the many sources of protein foods. In people with healthy kidneys, excess phosphorus is excreted in their urine. However, in patients with chronic renal failure, the kidneys are unable to maintain a delicate balance between phosphorus and calcium levels in the blood. Phosphorus is not excreted efficiently and thus builds up in the blood, a condition called hyperphosphatemia. Uncontrolled hyperphosphatemia causes a calcium-phosphate complex to precipitate in soft tissues, such as arteries, essentially turning them into bone. Hyperphosphatemia also causes increased secretion of the parathyroid hormone, which in turn causes bone degradation. Because a reduced dietary amount of phosphate is generally inadequate in reversing hyperphosphatemia, oral administration of certain phosphate binders has been suggested. Phosphate binders include calcium or aluminum salts which complex with phosphate to form insoluble calcium and aluminum salts. The long use of calcium and aluminum salts leads to hypercalcemia and aluminum toxicity.
Anion-exchange resins, some in the chloride form, have been recently suggested for use in binding phosphate and in the

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