OLEOGELS IN UV ABSORBER COMPOSITIONS

Abstract

Disclosed is the use of oleogels (a) for increasing the sun protection factor of sunscreens comprising at least one organic or inorganic UV filter (b).

Claims

1. A method of increasing the sun protection factor of sunscreens, the method comprising: adding an oleogel (a) to at least one organic or inorganic UV filter (b) to provide a sunscreen composition comprising the oleogel and the at least one organic or inorganic UV filter, wherein the oleogel comprises an oil or lipid in a stationary phase and a gel former.

2. The method according to claim 1 wherein the stationary phase of the oleogel (a) is selected from (sp.sub.1) Guerbet alcohols, (sp.sub.2) esters of linear C.sub.6 C.sub.24 fatty acids with linear C.sub.3-C.sub.24 alcohols, (sp.sub.3) esters of branched C.sub.6-C.sub.13carboxylic acids with linear C.sub.6-C.sub.24 fatty alcohols, (sp.sub.4) esters of linear C.sub.6-C.sub.24 fatty acids with branched alcohols, (sp.sub.5) esters of hydroxycarboxylic acids with linear or branched C.sub.6-C.sub.22 fatty alcohols, (sp.sub.6) esters of linear and/or branched fatty acids with polyhydric alcohols, (sp.sub.7) triglycerides based on C.sub.6-C.sub.10 fatty acids, (sp.sub.8) liquid mono-/di-/tri-glyceride mixtures based on C.sub.6-C.sub.18 fatty acids, (sp.sub.9) esters of C.sub.6-C.sub.24 fatty alcohols and/or Guerbet alcohols with aromatic carboxylic acids, (sp.sub.10) esters of C.sub.2-C.sub.12dicarboxylic acids with linear or branched alcohols having from 1 to 22 carbon atoms or polyols having from 2 to 10 carbon atoms and from 2 to 6 hydroxy groups, (sp.sub.11) vegetable oils, (sp.sub.12) branched primary alcohols, (sp.sub.13) substituted cyclohexanes, (sp.sub.14) linear and branched C.sub.6-C.sub.22 fatty alcohol carbonates, (sp.sub.15) Guerbet carbonates, (sp.sub.16) esters of benzoic acid with linear and/or branched C.sub.6-C.sub.22alcohols, (sp.sub.17) linear or branched, symmetric or asymmetric dialkyl ethers having a total of from 12 to 36 carbon atoms, (sp.sub.18) silicone oils, (sp.sub.19) aliphatic or naphthenic hydrocarbons, (sp.sub.20) monoesters of fatty acids with alcohols having from 3 to 24 carbon atoms, (sp.sub.21) isopropyl myristate, (sp.sub.22) isononanoic acid C.sub.16-C.sub.18alkyl esters, (sp.sub.23) stearic acid 2-ethylhexyl ester, (sp.sub.24) cetyl oleate, (sp.sub.25) glycerol tricaprylate, (sp.sub.26) coconut fatty alcohol caprinate/caprylate (sp.sub.27) n-butyl stearate (sp.sub.28) dicarboxylic acid esters, (sp.sub.29) diol esters, (sp.sub.30) polyols and (sp.sub.31) di- and/or trivalent metal salts.

3. The method according to claim 1, wherein the stationary phase of the oleogel (a) is selected from Dibutyl Adipate and Diethylhexyl Carbonate.

4. The method according to claim 1, wherein the gel former of the oleogel (a) is selected from (gf.sub.1) stearalkonium hectorite (bentonite), (gf.sub.2) gelatine, (gf.sub.3) silica, (gf.sub.4) montmorillonite, (gf.sub.5) monoglyceridees and diglycerides, (gf.sub.6) polysaccharides, (gf.sub.7) pectins and (gf.sub.8) specific polymers.

5. The method according to claim 1, wherein the gel former of the oleogel (a) is selected from (gf.sub.1) stearalkonium hectorite in combination with propylene carbonate.

6. The method according to claim 1, wherein the oleogel (a) is formed from the stationary phase components (sp.sub.29) dicarboxylic acid esters or (sp.sub.14) linear and branched C.sub.6-C.sub.22 fatty alcohol carbonates and the gel former (gf.sub.1) stearalkonium hectorite and (gf.sub.8) specific polymer.

7. The method according to claim 1, wherein the UV filter (b) is selected from (b.sub.1) triazine derivatives, (b.sub.2) hydroxybenzophenone derivatives, (b.sub.3) Methoxydibenzoylmethane derivatives, (b.sub.4) substituted acrylates, (b.sub.5) cinnamic acid derivatives, (b.sub.6) salicylic acid derivatives, (b.sub.7) benzotriazole derivatives; and (b.sub.8) inorganic pigments.

8. (canceled)

9. The method according to claim 7, wherein the UV filter (b) comprises a compound of formula (TR2): ##STR00016##

10.-22. (canceled)

23. The method according to claim 8, wherein the UV filter (b) comprises a mixture comprising the compound (TR2), compound (TR4), and compound (BP2): ##STR00017##

24. The method according to claim 23, wherein: the gel former is (gf.sub.1) stearalkonium hectorite and the stationary phase is selected from Dibutyl Adipate and Diethylhexyl Carbonate; and

25. Cosmetic composition, comprising (a) a stable oleogel and (b) at least one organic or inorganic UV filter.

26. The method according to claim 8, wherein: the stationary phase is a non-continuous phase, is present in an amount of 10-78.2 wt. % based on the sunscreen composition, and is dibutyl adipate or diethylhexyl carbonate; the gel former in the form of a three-dimensional meshwork with the stationary phase immobilized therein, is present in an amount of 3.25-13 wt. % based on the sunscreen composition, and is selected from the group consisting of: (gf.sub.1) stearalkonium hectorite (bentonite), (gf.sub.2) gelatine, (gf.sub.3) silica, (gf.sub.4) montmorillonite, (gf.sub.6) polysaccharides, and (gf.sub.7) pectins; and the UV filter (b) is present in an amount of 5-15 wt. % based on the sunscreen composition, and is distributed in the oleogel (a).

Description

EXAMPLES

Example 1: Sun Protection Factors of Oleogels—Influence of the Oil Polarity of a Sunscreen Formulation on its Sun Protection Factor

[0173] Oleogels of constant UV absorber composition but differing in emollient polarity are prepared. In a first trial, six formulations with different oils are sent to in vivo sun protection factor (SPF) determination. They all show extremely high SPF-values combined with a very high variability, making a meaningful evaluation impossible.

[0174] Using the same UV absorber composition, two oils are selected and the gel-former concentration is varied from zero up to the concentration used in the first study and one intermediate concentration in addition, resulting in six different samples. Again, the formulations are sent for in vivo SPF determination.

[0175] As oils Dibutyl Adipate and Diethylhexyl Carbonate (stationary phase) are used, the properties of which are listed in Table EX1. The results are summarized in Table EX2 and the complete information for the six formulations is shown in Table EX3.

TABLE-US-00003 TABLE EX1 Oil properties Interf. tension to water, γ (mN/m) Log P.sub.octanol/water δ(MPa.sup.1/2) Dibutyl Adipate 14.3 3.9 18.9 Diethylhexyl Carbonate 29.1 6.8 17.1

[0176] The smaller the interfacial tension of the oil towards water [1], the more polar it is. This is in line with the values of Log P.sub.octanol/water. The calculated Hildebrand solubility parameters δ are quite similar for both oils, indicating that their solubilizing capacities should be comparable.

[0177] As gel-former Steralkonium Hectorite (Bentone 27) is used in combination with Propylene Carbonate. Bentone 27 is a hydrophobically modified sheet silicate. The average dimensions of a clay platelet are 80×800×1 nm. Addition of Propylene Carbonate helps in developing the network structure of the gel-forming agent in the oil.

Results of In Vivo SPF Measurements

[0178] The UV absorber composition employed in all formulations is 5% Uvinul A plus, 2.5% Uvinul T150 and 3% Tinosorb S. Using the latest version of the BASF Sunscreen Simulator, for this composition a calculated SPF of 20.8 is obtained.

[0179] The results of the in vivo SPF screenings, performed in two testing institutions, are shown in Table 2.

TABLE-US-00004 TABLE EX2 Results of in vivo SPF Screenings Concentration of Bentone 27 0 % 6.5 % 13 % SPF with Dibutyl Adipate  7.1 ± 2.9 27.7 ± 7.3 30.8 ± 7.6 SPF with Diethylhexyl Carbonate 10.8 ± 1.4 28.4 ± 5.7 24.1 ± 6.9

[0180] It is evident from Table EX2 that the formulations without the gel-forming agent show SPF values much smaller than expected from the calculation, whereas addition of gel-former leads to a dramatic increase of the SPF, exceeding the expected value. Obviously, it does not matter for the in vivo results, whether the concentration of Bentone 27 is 6.5% or 13%.

TABLE-US-00005 TABLE EX3 Compositions of Formulations and in vivo SPF Screening Results OG-01 OG-02 OG-03 OG-04 OG-05 OG-06 INCI-Name (%) (%) (%) (%) (%) (%) Part Diethylamino  5.00  5.00  5.00  5.00  5.00  5.00 A Hydroxybenzoyl Hexyl Benzoate Ethylhexyl Triazone  2.50  2.50  2.50  2.50  2.50  2.50 Bis-Ethylhexyloxy-  3.00  3.00  3.00  3.00  3.00  3.00 phenol Methoxyphenyl Triazine Dibutyl Adipate 86.80 78.15 69.50 Diethylhexyl Carbonate 86.80 78.15 69.50 Part Stearalkonium  6.50 13.00  6.50 13.00 B Hectorite Part Propylene Carbonate  2.15  4.30  2.15  4.30 C In vivo SPF Proderm  7.1 ±  27.7 ±  30.8 ±  10.8 ±  28.4 ±  24.1 ± Screening Results  2.9  7.3  7.6  1.4  5.7  6.9 Institute  4.9 ± n.d.  56.7 ±  8.3 ± n.d.  30.4 ± Schrader  2.2  15.9  1.9  6.8

Results of Viscosity Measurements

[0181] For low viscosities a Brookfield DV-Ill with LV spindles was used, and for high viscosities a Brookfield DV-III Ultra with RV spindles.

TABLE-US-00006 TABLE EX4 Results of Viscosity Measurements Concentration of Bentone 27 0% 3.25% 6.5% 13% Viscosity with Dibutyl Adipate 18 mPa.Math.s 32 mPa.Math.s  513 mPa.Math.s 5.Math.10.sup.5 mPa.Math.s Viscosity with Diethylhexyl Carbonate 21 mPa.Math.s 62 mPa.Math.s 1560 mPa.Math.s n.d.

[0182] The results in Table EX4 show a dramatic increase of the viscosity with higher gel-former concentrations.