Polyurethanes as topical skin protectants

Details Polyurethanes as topical skin protectants Polyurethanes as topical skin protectants

1998-10-09

2001-08-21

Page, Thurman K. (Department: 1615)

Drug, bio-affecting and body treating compositions

Topical body preparation containing solid synthetic organic...

Skin cosmetic coating

C424S401000, C424S045000, C514S938000, C514S944000

Reexamination Certificate

active

06277364

ABSTRACT:

TECHNICAL FIELD
This invention relates to the protection of skin from material that is harmful to the skin or substances that are capable of penetrating the skin. In particular, the invention relates to the use of polyurethanes for such protection.
BACKGROUND
The outer skin layer (epidermis) forms a natural barrier to harmful substances from entering the body from the outside world. However, both hydrophilic and hydrophobic substances, including substances harmful to the body, are capable of penetrating across the stratum corneum layer into the viable skin tissues. Additionally, when the skin is compromised by cuts, abrasions, rashes, and the like, infectious agents such as viruses or bacteria may more readily enter the body. Finally, the skin may itself be harmed by commonly used noxious agents, for example toxic chemicals used in the laboratory, in industry, and at home.
One method commonly used to protect skin against harmful substances is, of course, the wearing of latex or rubber gloves. However, in general gloves are uncomfortable to wear for extended periods of time because of perspiration build-up, they reduce tactile sensitivity, and gloves are themselves quite susceptible to tearing, formation of pinholes, etc., with the consequent breakdown of protection.
The foregoing discussion is addressed largely to the protection of the hands, but can equally apply to other areas of the body, in particular the face, which is another area for which protection is often sought. The conventional mode of protection for the face is a mask, for example a plastic face mask. However, wearing a mask is uncomfortable because of perspiration build-up, and tends to diminish clarity and scope of vision. There are also occasions when the whole body may need protection from exposure to harmful substances, and in these situations protective body suits are worn. Such body suits incorporate all of the disadvantages of gloves or face mask mentioned above.
It would therefore be advantageous to have a means of protecting skin from harmful substances that does not require the use of gloves, face masks, or whole body suits. Such a means of protection should guard against toxic substances harmful to the skin itself, and substances capable of penetrating the skin barrier, such as viruses, bacteria, parasites, poisonous gases, toxic agents such as pesticides and herbicides, agents used as chemical weapons, for example mustard gases or neurotoxic agents, chemicals, and the like. The skin protectant should be simple and uncomplicated to apply, and not easily removed by water and aqueous environments. Greater skin protection would be provided if the protecting agent not only formed a barrier on the skin surface, but also was absorbed into the outer layer of the skin, i.e. the stratum corneum itself. Its presence in the stratum corneum would enhance efficiency as well as duration of action, in part due to the increased resistance to removal by friction or wiping. In this manner, a durable barrier would be formed that is not easily removed inadvertently or by solvents. Clearly this would be desirable, because in this manner the protective barrier function of the stratum cornea itself would be enhanced, and the barrier would not merely form a thin layer above the skin surface.
RELEVANT LITERATURE
Polyurethane hydrogels are disclosed for uses including cosmetic, biological and medical applications, such as carrier and delivery systems for pharmacologically active agents in Chvapil, et al., U.S. Pat. No. 4,913,897 and Gould, et al., U.S. Pat. No. 5,000,955, including the use of hydrogel solutions to form hydrophilic protective films on the skin.
Chess, et al., in U.S. Pat. Nos. 4,971,800, 5,045,317, and 5,051,260, disclose compositions comprising hydroxy-terminated polyurethanes that are useful for enhancing the cutaneous penetration of topically or transdermally delivered pharmacologically active agents. In Quigley, et al., WO 93/21904, assigned to the assignee of the present application, it is disclosed that such polyurethanes are also capable of increasing deposition of retinoic acid and sunscreens on and in the skin.
SUMMARY OF THE INVENTION
One aspect of the present invention relates to a topical composition for protecting the skin of a mammal, comprising: a polyurethane of Formula (I):
H-[-(YR)
m
—OC(O)NH—X—NHC(O)]
n
——(YR)
m
—OC(O)NH—X—NHC(O)O—(RY)
m
——[C(O)NH—X—NHC(O)O—(RY)
m
-]
n′
—H   (I)
wherein:
X is an alkylene or alkenylene radical containing from 1 to about 20 carbon atoms, or a cycloalkylene or cycloalkenylene radical containing from about 5 to 20 carbon atoms, or a mononuclear or fused ring arylene radical containing from about 6 to about 10 carbon atoms, unsubstituted or substituted with one or more lower alkyl, lower alkoxy, lower alkoxy-substituted lower alkyl, nitro or amino groups or halogen atoms;
Y is oxygen, sulfur or —NR
1
—, where R′ is hydrogen or lower alkyl;
R is the same or different, and is chosen from alkylene, alkenylene, —SiR
2
R
3
—, and —CR
2
R
3
—NR
4
—CR
2
R
3
—, wherein R
2
, R
3
and R
4
are independently hydrogen or lower alkyl;
m is an integer selected to provide a (YR) moiety having a molecular weight of from about 40 to about 10,000; and
n and n′ are the same or a different integer from 0-30 inclusive, correlated with m so as to provide a polyurethane compound having a molecular weight of up to about 200,000; and optionally a diluent; in the absence of a pharmacologically active agent.
Another aspect of the invention relates to a method for protecting the skin of a mammal, comprised of applying an effective amount of a polyurethane of Formula (I), optionally combined with a diluent, to the skin of a mammal.
Yet another aspect of the invention relates to an article of manufacture, comprising a topical composition comprising a polyurethane of Formula (I), and optionally, a diluent in combination with labeling instructions for application of said topical composition for the protection of skin.
DESCRIPTION OF SPECIFIC EMBODIMENTS
Definitions
As used herein:
“Alkyl” means a branched or unbranched saturated monovalent hydrocarbon radical containing 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, tert-butyl, butyl, n-hexyl, dodecyl, and the like, unless otherwise indicated. “Lower alkyl” means a branched or unbranched saturated monovalent hydrocarbon radical containing 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, tert-butyl, butyl, n-hexyl and the like, unless otherwise indicated.
“Lower alkoxy” means the group —O—(lower alkyl) wherein lower alkyl is as herein defined.
“Alkylene” means a branched or unbranched saturated divalent hydrocarbon radical containing about 1 to 20 carbon atoms, such as methylene, trimethylene, dimethyltrimethylene, ethylene, 1,2-propylene, 1,4-butylene, 1,3-butylene, 1,5-pentylene, 1,3-pentylene, 1,6-hexylene, 1,12-docecylene, and the like. Similarly, “cycloalkylene” means a saturated divalent hydrocarbon radical containg from about 5 to 20 carbon atoms, such as cyclopentylene and cyclohexylene.
“Alkenylene” means a branched or unbranched unsaturated divalent hydrocarbon radical containing about 1 to 3 double bonds and about 2 to 20 carbon atoms, such as ethene, 1-propene, 1-butene, 3-methylbut-1-ene, 1-pentene, 2-methylpent-1-ene, 1-hexene, 1-docecene, and the like. Similarly, “cycloalkenylene” means an unsaturated divalent hydrocarbon radical containing from about 5 to 20 carbon atoms such as cyclohexenylene.
“Halo” or “halogen” means fluoro, chloro, bromo, or iodo.
The term “aryl” or “arylene” refers to a monovalent unsaturated aromatic carbocyclic radical having a mononuclear or single ring (e.g., phenyl) or two fused rings (e.g., naphthyl, biphenyl, indanyl, 1,2,3,4-tetrahydronaphthyl, benzocycloheptane), containing from about 6 to about 10 carbon atoms, and which can optionally be mono-, di- or tri-substituted, independently, with —OH, —COOH, lower alkyl, lower alkoxy, halo, nitro, amino, alkylamino, dialkylamino, trifluoromethyl and/or cyano.
“Optional” or “o

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