Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Reexamination Certificate
2001-03-15
2003-04-01
Qazi, Sabiha (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
C424S497000, C424S489000, C424S070110, C424S078370, C424S078080, C514S785000, C560S171000, C560S172000, C560S176000, C560S183000, C525S400000
Reexamination Certificate
active
06540987
ABSTRACT:
FIELD OF INVENTION
This invention relates to new biodegradable polymers and their use in the cosmetic field. The instant invention is also directed to biodegradable polyester polymers. This invention also relates to new biodegradable polyester polymers derived from hydroxy fatty acids and lower alkyl hydroxy acids or alkyl polyhydroxy diacids. The invention is further directed to cosmetic compositions containing biodegradable polyester. This invention further relates to biofriendly polyester polymers and copolymers derived from lactic acid, other hydroxy acids, ricinoleic acid and other hydroxy fatty acids. The present invention also relates to polyhydroxy polyalkanoates and their use as a vehicle for cosmetic products.
The present invention also relates to biodegradable polyester polymeric compositions especially poly[(lactic acid)-co-(ricinoleic acid)] and their use in cosmetic applications. The instant invention also relates to novel polyester polymers, polymer compositions and methods for using such polymers and compositions in personal care applications. In general terms, the polyester polymers and polymer compositions of the present invention are believed to be useful in the cosmetic treatment of keratin-containing substrates. Keratin substrates include, but are not limited to, animal and human hair, skin and nails.
More particularly, the instant invention relates to polyester polymer compositions and methods for treating keratin in which a cosmetically acceptable formulation is made with the instant polyesters as a cosmetic vehicle. Preferably, the cosmetically acceptable medium is a hair care product such as a shampoo, conditioner, styling product or rinse, or a skin care product such as a cleaner, lotion or cream.
The invention further relates to improved waterproof sunscreen compositions containing the polyesters of the instant invention.
The invention also relates to waterproof, high-SPF sunscreen compositions comprising an emollient/solvent system and sunscreen agent(s) in a polyester vehicle suitable for topical administration.
The invention is also concerned with waterproof sunscreen formulations and methods of protecting human skin from the effects of harmful ultraviolet radiation, e.g., erythema and burning, using effective amounts of the same.
BACKGROUND OF THE INVENTION
Even though cosmetic preparations have been a staple of commerce for centuries, there continues to be a continual expansion of cosmetic markets, and proliferation of new products. The field of skin care products has grown tremendously as new naturally occurring and synthetic polymeric materials have been identified. Processing equipment and techniques have also become more sophisticated, so that many of the current cosmetic products available over the counter, have a high level of uniformity and wholesomeness, but also impart substantive pharmacologic and nutritive properties not realized in older preparations.
The goal of modern cosmetics is to achieve multiple effects simultaneously, such as moisturizing, increased pliancy, drug or nutrient delivery, texturizing, environmental protection, and coloration. Some of these objectives inherently require substances which are water compatible such as humectants, and others require lipid compatible substances such as emollients. The largest class of cosmetic mixtures are emulsions of oil and water based fractions, and may be either oil in water (O/W) or water in oil (W/O), or both. For a review of the various physical forms and processes of making mixtures such as true emulsions, microemulsions, gels, and liposomes, see Fox, C., “Cosmetic Vehicles., Advances in Cosmetic Science and Technology, part 4,” Cosmetics and Toiletries, 110: 59 (1995).
These emulsions have both occlusivity and humectancy. In occlusivity, a non-irritating moisture barrier is established on the surface of the skin, to prevent loss of moisture. Typical materials are petroleum jelly, mineral or vegetable oils, silicones, waxes, fatty acids, and esters. Typical humectants, which attract water and help bind water to the skin, include glycerin, sorbitol, sodium lactate, and sodium pyrrolidone carboxylate, are beneficial in hydrating the stratum corneum and improving its viscoeleastic behavior (See Williams and Schmitt, eds., Chemistry and Technology of the Cosmetics and Toiletries Industry, 2nd ed., Blackie Academic and Professional, London: 1996).
Most emulsions require one or more stabilizers to maintain the microdispersion, and to prevent collapse and separation of the blend. A widely used stabilizer system utilizes stearic acid in the oil phase, and tri-, di-, or monoethanolamine in the aqueous phase. The resulting ethanolamine stearate is an excellent stabilizer. Combinations of intermediate chain length (C
6
-C
12
) aliphatic alcohols, esters, and carboxylic acids may act as stabilizers. Cetyl alcohol (C
16
) is commonly used in conjunction with triethanolamine to impart both soft “feel” and stabilization of the emulsion. Cetyl palmitate, isolated from natural sources, is a preferred stabilizer and carrier for other ingredients.
Many cosmetic preparations require thickeners to provide the desired viscosity. These thickeners are often used when the lubricity of the oil fraction is heightened by a high unsaturated oil composition of the cosmetic. Typical thickeners include coconut diethanolamide, cellulose and certain ether derivatives such as hydroxyethylcellulose or hydroxypropylcellulose, carrageenan, which is a linear sulfated polysaccharide of D-galactose and D-anhydro-D-galactose. For a good discussion of the role of thickeners in cosmetic preparation, see Knowlton, et al., eds., Handbook of Cosmetic Science and Technology, 1st ed., Elsevier, Oxford: 1993).
Since the advent of polymer surfactant chemistry, a large and varied number of surface active compounds have been available for incorporation into cosmetics. Because surfactants tend to mobilize natural lipid, there is a pronounced tightening effect on the skin associated with their use, presumably by their residues binding to keratin. This effect is most severe using sodium lauryl sulfate, and is much diminished in the use of potassium myristate. The use of surfactants, of course, has an important cleaning function, so that they are common ingredients in cleansing creams. Since these creams are first spread onto the skin and then removed almost immediately by tissue wiping, surface contact is minimized.
There have been many studies of cosmetic additives which enhance the penetration of the beneficial ingredients into the lower strata of the epidermis. Similarly there have been many studies of the physiology, histology, and biochemistry of the epidermis and dermis and their relation to absorption. Among those compounds studied, the following have been identified as promoting adsorption and penetration (also termed “flux”) of chemicals through the lipid-dominated interstices between cells of the lamellar layer: propylene glycol either alone or in combination with unsaturated fatty acids, and propylene glycol diesters of caprylic and capric acids. Solvents such as DMSO, ethanol, tetrahydrofuran, and isopropanol are known to deplete interstitial lipids leading to increased penetration of indicator drugs. These may be useful for “patch” type drug delivery devices, but have limited value in routine cosmetics because of their irritant properties. The goal of these ingredients is to promote adsorption and migration of beneficial substances through the lipid deposits without disrupting the essential structure of the skin.
A popular class of cosmetic additives (15 percent of total cosmetic sales) is the so-called sunscreens. UV light from the sum has a spectrum of wavelengths ranging from 400 nm down to less than 290 nm. Light having a wavelength of 400-320 is known as UV-A, that having a wavelength of 320-290 is called UV-B, and that having a wavelength of less than 290 nm is UV-C. UV-B has the greatest potential for causing skin damage and is associated with accelerating skin ageing, wrinkling, epidermal cracking an
Desai Bharat B.
Weipert Paul David
Angres Isaac A.
Ethox Chemicals LLC
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