Topical composition for delivery of salicylates
The present invention provides a self-emulsifiable composition and a stable topical emulsion comprising same, which comprises salicylate, oils and surfactants and which does not require organic solvents. The invention also provides methods for manufacturing the compositions. The topical compositions of the invention can be used to enhance delivery of salicylates and are useful in the prevention and treatment of pain and inflammation.
1 . A self-emulsifiable composition that can be used in the formulation of a topical salicylate emulsion composition comprising
(a) a salicylate;
(b) oils comprising a mixture of aromatic and aliphatic oily excipients in a ratio of 1:2 to 5:1 by weight;
(c) non-ionic surfactants.
2 . A self-emulsifiable composition of claim 1 comprising 20-50% by weight of salicylate.
3 . A self-emulsifiable composition of claim 1 wherein the salicylate is selected from the group consisting of Methyl Salicylate, Ethyl Salicylate, Glycol Salicylate, Ethylhexyl Salicylate, Phenyl Salicylate, Homosalate, Sodium Salicylate, Trolamine Salicylate, Choline Salicylate, and Arginine Salicylate.
4 . A self-emulsifiable composition of claim 1 comprising 5-25% by weight of oils.
5 . A self-emulsifiable composition of claim 4 wherein the oils are selected from the group consisting of glycerides, aliphatic esters, ethers and alkanes, tocopherols, tocopherol esters, esters of salicylic acid and benzoic acid.
6 . A self-emulsifiable composition of claim 1 comprising 5-25% by weight of non-ionic surfactants.
7 . A self-emulsifiable composition of claim 1 , wherein the composition forms a stable oil-in-water emulsion upon dilution with water phase.
8 . An emulsion composition comprising the self-emulsifiable composition of claim 7 and a water phase wherein the self-emulsifiable composition comprises 10-60% of the emulsion.
9 . An emulsion composition comprising the self-emulsifiable composition of claim 1 and a water phase, in a ratio from about 1:20 to about 2:1 of water phase relative to the composition, forms a stable emulsion, suitable for preparation of semi-solid topical formulations.
10 . An emulsion composition of claim 9 comprising 5% to 25% by weight of salicylate.
11 . An emulsion composition according to claim 10 wherein the salicylate is predominantly associated with the oil phase of the emulsion after dilution with water phase.
12 . A composition comprising an emulsion of claim 11 , wherein the emulsion additionally comprises one or more rheology modifiers producing a semisolid composition suitable for topical application.
13 . A composition for the preparation of the salicylate loaded topical formulation comprising salicylate, oil phase, oil phase modifiers, and surfactant or mixture of surfactants.
14 . A composition as set forth in claim 13 wherein the oil phase of the emulsion comprises a mixture of aliphatic and aromatic components.
15 . A composition as set forth in claim 14 wherein the aliphatic component of said oil phase is selected from the group consisting of glycerides, aliphatic esters, ethers and alkanes.
16 . A composition as set forth in claim 15 wherein the aromatic component of said oil phase is selected from the group consisting of tocopherols, tocopherol esters, esters of salicylic acid and benzoic acid.
17 . A composition as set forth in claim 14 wherein the aliphatic and aromatic components ofthe oil phase are present in a ratio between 1:2 and 5:1 by weight.
18 . A composition as set forth in any one of claim 17 wherein the oil phase modifiers are polar compounds, soluble in the oil phase.
19 . A composition as set forth in claim 18 wherein the polar compounds are aliphatic alcohols or ketones, or a combination thereof.
20 . A composition as set forth in claim 19 wherein the polar compounds are camphor or menthol or a combination thereof.
21 . A composition as set forth in claim 20 wherein the camphor and menthol mixture constitutes between 5% and 80% of the oil phase by weight.
22 . A composition as set forth in claim 21 wherein menthol and camphor are present in a ratio between 1:2 and 2:1 by weight.
23 . A composition of claim 9 , comprising oil droplets of submicron size.
24 . A composition of claim 23 wherein the oil droplets are less than 30 nm.
25 . A process for the preparation of a stable submicron emulsion of salicylates comprising oil droplets of submicron size, wherein the process comprises dilution of a self-emulsifiable composition of claim 1 followed by agitation, wherein the process provides spontaneous formation of a submicron emulsion and does not involve the application of high energy/high force emulsification, such as high pressure homogenization, high shear homogenization, sonication, or passage through microporous membranes.
26 . The process of claim 25 , wherein the oil droplets are less than 30 nm.
27 . A method for treating an inflammatory and/or pain condition comprising administering an effective amount of the composition of claim 9 to a patient in need thereof.