Pramoxine compositions
The invention provides a topical o/w emulsion which moisturizes, and protects, repairs or restores the skin lipid barrier of a mammal. The topical o/w emulsion composition comprises: a) a discontinuous oil phase; b) a continuous aqueous phase comprising water; c) a thickening agent; d) at least one lamellar membrane structure comprising (i) a phospholipid, (ii) a fatty alcohol, and (iii) a fatty acid; e) a pharmaceutically acceptable active agent; and f) optionally a dermatologically acceptable excipient. In one embodiment, the composition, in use, has a water vapor transmission rate of less than or about 75 g·m −2 ·hr −1 measured in vitro using the modWVTR test methodology.
1. A topical oil-in-water emulsion composition comprising:
(a) from about 5% to about 70% of a discontinuous oil phase comprising hydrogenated castor oil, mineral oil, and caprylic/capric triglyceride;
(b) from about 10% to about 90% of a continuous aqueous phase comprising water and from about 5% to about 15% by weight of glycerine;
(c) a thickening agent;
(d) at least one lamellar membrane structure comprising
(i) from about 0.5% to about 5% by weight of a phospholipid component comprising hydrogenated phosphatidylcholine,
(ii) from about 2% to about 15% by weight of a fatty alcohol component comprising behenyl alcohol or a mixture of behenyl alcohol and cetyl alcohol,
(iii) from about 0.25% to about 2.5% by weight of a fatty acid component comprising behenic acid, and
(iv) from about 0.1% to about 5% by weight of an ester of a branched fatty acid and a branched fatty alcohol component comprising isostearylisostearate;
(e) 1% pramoxine, optionally as the pharmaceutically acceptable salt; and
(f) optionally a dermatologically acceptable excipient wherein the fatty alcohol and the phospholipid are present in a weight ratio of from about 10:1 to about 1:1; the fatty alcohol and the fatty acid are present in a weight ratio of from about 10:1 to about 1:1; and the fatty alcohol and the ester are present in a weight ratio of from about 10:1 to about 1:1; and wherein in use the composition has a water vapor transmission rate of less than about 65 gm −2 hr −1 measured in vitro using the modWVTR test methodology.
2. The composition according to claim 1 wherein the weight ratio of the hydrogenated phosphatidylcholine:behenyl alcohol:behenic acid; isostearyl isostearate is about 2.17:10:1.57:1.57.
3. The composition claim 1 wherein the weight ratio of phospholipid:fatty alcohol:fatty acid:ester is about 1.4:6.4:1:1.
4. The composition according to claim 1 comprising 10% by weight of behenyl alcohol.
5. The composition according to claim 1 , wherein the dermatologically acceptable excipient is selected from an antioxidant, a chelating agent, a preservative, a colorant, a sensate, a moisturizer, a humectant, a pH adjusting agent, and combinations and mixtures thereof.
6. A method for moisturizing, the skin of a mammal, the method comprising applying to the skin of the mammal in need thereof an effective amount of a topical oil-in-water emulsion composition comprising a composition claim 1 .
7. A method for reducing the itchiness of the skin of a mammal, the method comprising applying to the skin of the mammal in need thereof an effective amount of a topical oil-in-water emulsion composition comprising a composition claim 1 .
8. A method for applying local anesthesia to the
skin of a mammal, the method comprising applying to the skin of the mammal in need thereof an effective amount of a topical oil-in-water emulsion composition comprising a composition according to claim 1 .