10-HYDROXYSTEARIC ACID COMPOSITIONS

Abstract

The present invention relates to topical compositions comprising 10-hydroxystearic acid or a salt thereof and at least one nonionic emulsifier. The present invention also relates to a method to retard or inhibit the re-crystallisation of 10-hydroxystearic acid or a salt thereof in a topical composition, said method comprising formulating 10-hydroxystearic acid or a salt thereof in the presence of at least one nonionic emulsifier.

Claims

1. A topical composition comprising 10-hydroxystearic acid or a salt thereof and at least one nonionic emulsifier, with the proviso that the composition is free of isobutylparabene.

2. A topical composition according to claim 1, which is also free of a cooling agent and/or an exothermic agent.

3. The topical composition according to claim 1, wherein the amount of the 10-hydroxystearic acid or a salt thereof is selected in the range of 0.001 to 5 wt.-%, preferably in the range of 0.01 to 3 wt.-%, most preferably in the range of 0.1 to 2 wt.-%, such as in particular in the range of 0.1 to 1.5 wt.-%, based on the total weight of the composition.

4. The topical composition according to claim 1, wherein the amount of the nonionic emulsifier is selected in the range of 0.1 to 7 wt.-%, preferably in the range of 1 to 6 wt.-%, most preferably in the range of 1 to 5 wt.-%, based on the total weight of the composition.

5. The topical composition according to claim 1, wherein 10-hydroxystearic acid, in particular (R)-10-hydroxystearic acid is used.

6. The topical composition according to claim 1, wherein the at least one nonionic emulsifier is selected from the group consisting of esters of fatty alcohols, polyalkylenglycol alkyl ethers, polyalkyleneglycol fatty acid esters, glucoside alkyl ethers, alkyl glucose esters, glycerol alkyl esters, sorbitan fatty acid esters as well as block polymers of polyethylene glycol and polypropylene glycol.

7. The topical composition according to claim 1, wherein the at least one nonionic emulsifier is selected from the group consisting of C.sub.12-C.sub.22-alkylester of C.sub.12-C.sub.22-alcohols, polyethylene glycol alkyl ethers such as more preferably polyethylene glycol C.sub.12-C.sub.22-alkyl ether having an ethylenoxide number of 2 to 30, polyethylene glycol fatty acid esters such as more preferably polyethylene glycol C.sub.12-C.sub.22 fatty acid esters having an ethylenoxide number of 2 to 150, (polyglyceryl) alkylglucose alkyl esters, glycerol C.sub.12-C.sub.22 fatty acid esters and sorbitan mono fatty acid esters.

8. The topical composition according to claim 1, wherein the at least one nonionic emulsifier is selected from the group consisting of polyglycery-3 methylglucose distearate, cetearyl glucoside, methyl glucose sesquistearate, cetearyl olivate, sorbitan olivate, PEG-40 stearate, PEG-100 stearate, glyceryl stearate, steareth-2 and steareth-21.

9. The topical composition according to claim 1, wherein the topical composition comprises a co-emulsifier selected from the group of nonionic solid fatty alcohols having from 12 to 22 carbon atoms as well as mixtures thereof, preferably from cetyl alcohol, behenyl alcohol and cetearyl alcohol as well as mixtures thereof.

10. The topical composition according to claim 1, wherein the amount of co-emulsifier is selected in the range of 0.1 to 20 wt.-% based on the total weight of the composition, more preferably in the range of 0.5 to 10 wt.-%, most preferably in the range of 1 to 5 wt.-%, based on the total weight of the composition.

11. The topical composition according to claim 1, wherein the composition comprises a preservative selected from the group consisting of phenoxyethanol and ethylhexylglycerin as well as mixtures thereof.

12. The topical composition according to claim 1, wherein the topical composition is an O/W emulsion comprising an aqueous phase and an oily phase.

13. The topical composition according to claim 12, wherein the aqueous phase constitutes at least 50 wt.-% and the oily phase at least 10 wt.-%, based on the total weight of the composition.

14. A method to retard or inhibit the re-crystallisation of 10-hydroxystearic acid or a salt thereof in a topical composition, said method comprising formulating 10-hydroxystearic acid or a salt thereof in the presence of at least one nonionic emulsifier.

15. The method according to claim 14, wherein the at least one nonionic emulsifier is selected from the group consisting polyglycery-3 methylglucose distearate, cetearyl glucoside, cetearyl olivate, sorbitan olivate, methyl glucose sesquistearate, PEG-40 Stearate, PEG-100 stearate, glyceryl stearate, steareth-2 and steareth-21, as well as mixtures thereof.

16. The method according to claim 15, wherein the at least one nonionic emulsifier is selected from the group consisting PEG-40 Stearate, PEG-100 stearate, steareth-2 and steareth-21, as well as mixtures thereof.

Description

EXAMPLE 1

[0073] Various formulations using different emulsifiers (anionic (Ref) and nonionic (Inv)) have been prepared as outlined in Table 1 and 2. Initially, no crystals have been observed in any of the formulations by microscopy analysis. Then the formulations have been stored at room temperature and repeatedly been microscopically analyzed for re-crystallization of 10-hydroxystearic acid up to 3 months. The results thereof are outlined in Table 2.

TABLE-US-00001 TABLE 1 INCI Wt.-% A Butyl Methoxydibenzoyl Methane 3.0 Octocrylene 2.7 Homosalate 5.0 Ethylhexyl Salicylate 5.0 C.sub.12-15 Alkyl Benzoate 5.0 Cetearyl Alcohol 2.0 Behenyl Alcohol 1.0 BHT 0.1 Acrylates/C.sub.10-30 Alkyl Acrylate Crosspolymer 0.1 10-Hydroxystearic Acid 1.0 Emulsifier See table 2 Stearic Acid B Xanthan Gum 0.2 Disodium EDTA 0.1 Butylene Glycol 2.0 Sodium Hydroxide 0.1 Aqua Ad 100 C Phenoxyethanol; Ethylhexylglycerin 1.0

Preparation Procedure

[0074] 1st Heat part A to 90 C. and part B to 80 C.

[0075] 2.sup.nd Combine part A and B and homogenize 1 minute at 10.000 rpm.

[0076] 3.sup.rd Cool down while stirring.

[0077] 4.sup.th Add part C at 35 C. while stirring.

[0078] 5.sup.th At last, Cool down to RT while stirring.

TABLE-US-00002 TABLE 2 microscopy aspect crystallization Emulsifier wt.-% after Ref Potassium Cetyl phosphate 2.0 2 weeks Ref Stearic Acid 8.0 2 weeks Ref C.sub.20-22 Alkyl Phosphate (And) C.sub.20-22 2.0 2 weeks Alcohols Ref Glyceryl Stearate Citrate 2.0 2 weeks Ref Disodium Cetearyl Sulfosuccinate 1.0 2 weeks Inv Polyglyceryl-3 Methylglucose 3.0 6 weeks Distearate Inv Cetearyl Olivate (and) Sorbitan Olivate 4.0 12 weeks Inv Cetearyl Glucoside 1.5 6 weeks Inv Methyl Glucose Sesquistearate 2.5 6 weeks Inv PEG-100 Stearate (and) Glyceryl 3.5 No crystals Stearate after 3 months Inv Steareth-2 (and) Steareth-21 2.5/1.0 No crystals after 3 months

[0079] As can be retrieved from Table 2, the use of a nonionic emulsifier significantly retards or even inhibits the recrystallization of 10-hydroxystearic acid in a topical composition.

EXAMPLE 2

[0080] A formulation comprising a nonionic, PEG-based emulsifier (PEG-40 Stearate) and an anionic emulsifier (stearic acid) as outlined in table 3 has been prepared.

[0081] This formulation also did not result in any crystal formation, even after 3 months.

TABLE-US-00003 TABLE 3 INCI Wt.-% BHT 0.1 10-Hydroxystearic Acid 1.0 Stearic Acid 17.0 Isopropyl Myristate 10.0 PEG-40 Stearate 5.0 Stearyl Alcohol 3.0 Sorbic Acid 0.2 Xanthan Gum 0.3 Aqua Ad 100 microscopy aspect No crystals after 3 months crystallization after: