Drug – bio-affecting and body treating compositions – Topical body preparation containing solid synthetic organic...
Reexamination Certificate
1999-02-15
2001-07-17
Levy, Neil S. (Department: 1616)
Drug, bio-affecting and body treating compositions
Topical body preparation containing solid synthetic organic...
C424S043000, C424S047000, C424S059000, C424S065000, C424S069000, C424S078030, C424S078050, C424S078060, C424S078070, C424S078170, C424S078180, C424S078190, C424S405000, C424S407000, C424S420000, C424S486000, C424S401000, C525S411000, C525S413000, C525S450000, C514S772500, C514S772600, C514S772700, C514S830000, C514S887000, C514S919000, C514S944000, C514S945000, C514S947000, C514S969000, C514S772100, C514S772300, C514S772400
Reexamination Certificate
active
06261544
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to poly(hydroxy acid)/polymer conjugate formulations for cosmetic and dermatological skin applications, and methods of use thereof.
Skin disorders range from various cosmetic conditions to severe dermatologic diseases. Conventional treatments for many of these disorders have included topical applications of oils, emollients, humectants, drugs and medicaments. Such treatments have met with varying degrees of success.
It is also known to use hydroxy acids, especially alpha and beta hydroxy acids, in the treatment of various skin conditions, for example, as reviewed in U.S. Pat. Nos. 5,091,171 and 4,363,815 to Yu and Van Scott, which describe the use of various hydroxy acid monomers and oligomers (containing two or three units) in skin treatment. Other patents relating to skin treatment with hydroxy acids include U.S. Pat. Nos. 3,988,470, 4,105,782, 4,234,599,4,380,549, and 5,258,391. Others describing the use of hydroxy acids in skin treatment include EP 0 358 528 by Periera, U.S. Pat. No. 4,294,852 to Wildnauer et al., and U.S. Pat. No. 2,726,982 to Ochs.
While hydroxy acids are well-known in skin treatment, there are various problems inherent in their application to skin, especially from the point of view of safety. In particular, use of a formulation which contain free monomeric hydroxy acids results in an immediate one-time introduction of the full dosage upon application to the skin, which can cause peeling, chemical burning and even scarring of the skin. This problem is specially acute with the more concentrated doses described in the Yu et al patents, referred to above.
In principle, this problem can be overcome by polymerization of the hydroxy acids (HAs) to form polyhydroxy acids (PHAs). Polyhydroxy acids such as polylactic acid, polyglycolic acid, are polycaprolactone are well-known in the manufacture of degradable medical devices, such as sutures (for example, Vicryl®), absorbable sponges and fabrics, and other devices. They are suitable for such uses because PHAs become water-insoluble at relatively low degrees of polymerization. The polyhydroxy acids gradually degrade back to the monomeric acids in the presence of water or of bodily fluids at approximately neutral pH. The principal drawback of these materials is a mild degree of irritation or inflammation at the site during the degradation of the polymer. This is acceptable in the context of wound repair, but is less acceptable in treatment of the skin for relief of cosmetic problems.
Moreover, it is difficult to eliminate this effect by dissolving or dispersing the PHAs in solvent. It is known that polyhydroxy acids such as polyglycolic acid are not soluble in skin-compatible. solvents, but only in organic solvents such as hexafluoroacetone hexahydrate or hexafluoroisopropanol, acetone, and methylene chloride. Attempts to disperse pure PHAs in other components of a cosmetic formulation are thus difficult, and could lead to phase separation of a PHA-rich phase within the formulation, leading to gradations of different concentrations of the hydroxy acid on the skin to which the formulation is applied.
It is therefore an object of the invention to provide a safe, effective and easy method for alleviating the symptoms of a cosmetic or dermatologic skin condition.
It is a further object of the invention to provide a method for the controlled release of hydroxy acids onto the skin of a person to alleviate the symptoms of a cosmetic or dermatologic skin condition.
It is another object of the invention to provide a method for alleviating the symptoms of a cosmetic or dermatologic skin condition which combines the advantages of a humectant and an hydroxy acid.
It is a still further object of the invention to provide a method for alleviating the symptoms of a cosmetic or dermatologic skin condition by providing a formulation which results in substantially uniform application of hydroxy acids to the skin.
SUMMARY OF THE INVENTION
A method for alleviating the symptoms of a cosmetic or dermatologic skin condition is provided wherein an effective amount of a poly(hydroxy acid)/polymer conjugate in a pharmaceutically or cosmetically acceptable vehicle is topically applied to the skin. Vehicles include powders, lotions, gels, sprays, sticks, creams, ointments, liquids, emulsions, foams and aerosols. The conjugate consists of a backbone polymer having poly(hydroxy acids) or derivatives thereof coupled to the backbone to form a brush, linear or branched copolymer. Selection of the backbone can be used to impart desirable properties, as well as control the rate of degradation, and, in turn, the rate of release of hydroxy acids to the skin.
The conjugates can also be used as a method for delivering to the skin a physiologically active functional group, such as a fragrance, an anti-microbial such as a bactericide or fungicide, acne medication, wart remover such as salicylic acid with or without other hydroxy acids, a reductant to bleach skin spots such as hydroxyquinone, a nutrient such as vitamin A or other vitamins, and sunscreens.
DETAILED DESCRIPTION OF THE INVENTION
A method for alleviating the symptoms of a cosmetic or dermatologic skin condition has been developed in which an effective amount of a poly(hydroxy acid)/polymer conjugate in a pharmaceutically or cosmetically acceptable vehicle is topically applied to the skin.
Applications
As used herein, compositions referred to for cosmetic use, skin application, or topical use, encompass treatments and uses which are specifically medicinal as well as conventional cosmetic uses such as in beauty aids and toiletries.
By skin conditions is meant any skin condition whose symptoms can be alleviated by the poly(hydroxy. acid)/polymer conjugates described herein. Examples of skin conditions include dry skin, xerosis, ichthyosis, dandruff, brownish spots, keratoses, melasma, lentigines, age spots, liver spots, pigmented spots, blemishes, wrinkles, skin lines, fine lines, oily skin, acne, warts, eczema, pruritic skin, psoriasis, inflammatory dermatoses, disturbed keratinization, skin changes associated with aging, nail or skin requiring cleansers, conditioners or treatment, and hair or scalp requiring shampooing or conditioning.
Additional uses are associated with application to the skin of antibiotics, antifungals, pediculicides, antiperspirants, antipruritics, analgesics, anesthetics, treatments for blisters, canker sores, insect bites and diaper rash, insect repellents and sunscreens. Preferred uses of the conjugate are for dry skin or wrinkles.
Polymeric Conjugates
As discussed above, the hydroxy acids typically used in medicinal and cosmetic applications are hydroxy acid monomers or polymers of hydroxy acids.
In contrast, as described herein, hydroxy acid conjugates or copolymers have now been found to be advantageous, due to a more defined release rate and avoidance of concentration gradients.
The poly(hydroxy acid)/polymer conjugate may be represented by the formula
PaHb
where P is a polymer block having monomer subunits M, in which the monomer subunits are the same or different, and a plurality of which are not hydroxy acids; H is a poly(hydroxy acid) block; and a and b are integers of one or more and denote the number of P and of H blocks in the copolymer. The P blocks and H blocks can be joined in any convenient arrangement. Simple linear arrangements are contemplated, in which the blocks are joined P-H, P-H-P, or H-P-H. The last arrangement, which is a preferred embodiment, is readily made by polymerizing monomeric or dimeric hydroxy acid derivatives, such as lactide, glycolide, or caprolactone, onto a dihydroxy terminated compound such as a polyethylene glycol. Other arrangements of P and H include star copolymers or brush copolymers in which multiple H blocks are dependent from a single P chain, P-Hb where b is greater than 2. The alternative, PaH, where a is greater than two, is generally less preferable, but is possible if one or more of the hydroxy acids comprising block H contains more than one hydroxyl group, as with g
Avila Luis Z.
Barman Shikha P.
Coury Arthur J.
Pathak Chandrashekhar P.
Arnall Golden & Gregory LLP
Focal, Inc.
Levy Neil S.
LandOfFree
Poly(hydroxy acid)/polymer conjugates for skin applications does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Poly(hydroxy acid)/polymer conjugates for skin applications, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Poly(hydroxy acid)/polymer conjugates for skin applications will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2504960