Sunscreen composition

Abstract

A composition contains at least one sunscreen and a protein-PVP copolymer. The sunscreen may be organic and/or inorganic, particularly titanium dioxide. The protein-PVP copolymer improves the effectiveness of the sunscreen, resulting in increased SPF values of the composition.

Claims

1. A sunscreen emulsion composition, comprising: i) an oil phase comprising at least one of: a) 1-20 wt. % of an organic sunscreen, based on the total weight of the sunscreen emulsion composition; and b) 2-12 wt. % of titanium dioxide particles, based on the total weight of the sunscreen emulsion composition, wherein said titanium dioxide particles have a hydrophobic coating and have a median volume particle diameter of 24 to 42 nm; and ii) an aqueous phase comprising 0.2-1 wt. %, based on the total weight of the sunscreen emulsion composition, of a protein-polyvinylpyrrolidone (PVP) copolymer having a protein to PVP ratio in the range of 5-70:30-95 wt. %; wherein the sunscreen emulsion composition: 1) has an SPF value of greater than 10; and 2) has an increase in SPF value of greater than 8% per 0.1 wt. % of protein-PVP copolymer present in said sunscreen emulsion composition, relative to said sunscreen emulsion composition exclusive of the protein-PVP copolymer.

2. The emulsion composition of claim 1, wherein the organic sunscreen is selected from the group consisting of butyl methoxydibenzoylmethane, ethylhexyl methoxycinnamate, octocrylene, and mixtures thereof.

3. The emulsion composition of claim 1, wherein the titanium dioxide particles are dispersed in a dispersing agent.

4. The emulsion composition of claim 1, wherein the increase in the SPF value due to the presence of the protein-PVP copolymer is greater than 20%.

5. The emulsion composition of claim 1, wherein the emulsion composition comprises 0.3-0.5 wt. % of the protein-PVP copolymer.

6. The emulsion composition of claim 1, wherein the emulsion composition comprises 0.4 wt. % of the protein-PVP copolymer.

7. The emulsion composition of claim 1, wherein the SPF increase is obtainable at a concentration of 0.4 wt. % of the protein-PVP copolymer.

8. The emulsion composition of claim 1, wherein the sunscreen emulsion composition has an SPF value in the range of between 20-100.

9. The emulsion composition of claim 1, wherein the oil phase comprises both said organic sunscreen and said titanium dioxide particles.

10. The emulsion composition of claim 3, wherein the dispersing agent is polyhydroxystearic acid.

11. A method of improving sunscreen effectiveness, comprising combining a protein-PVP copolymer and sunscreen in an emulsion composition, wherein the improved sunscreen effectiveness is an increase in SPF value of greater than 8% per 0.1 wt. % of the protein-PVP copolymer present in said emulsion composition, relative to said emulsion composition exclusive of the protein-PVP copolymer, wherein the sunscreen comprises titanium dioxide particles having a hydrophobic coating, and wherein the emulsion composition is a sunscreen emulsion composition according to claim 1.

12. The method of claim 11, wherein the emulsion composition contains 2-40 wt. % of sunscreen incorporated into the oil phase of the emulsion composition based on the total weight of the emulsion composition.

13. The method of claim 12, wherein the sunscreen comprises both the titanium dioxide particles and an organic sunscreen.

14. The method of claim 13, wherein the organic sunscreen is selected from the group consisting of butyl methoxydibenzoylmethane, ethylhexyl methoxycinnamate, octocrylene, and mixtures thereof.

15. The method of claim 12, wherein the sunscreen in the oil phase comprises 2-20 wt. % of a metal oxide sunscreen, based on the total weight of the emulsion composition.

16. The method of claim 11, wherein the increase in the SPF value of the emulsion composition containing the added protein-PVP copolymer is greater than 20%, relative to said emulsion composition exclusive of the protein-PVP copolymer.

Description

EXAMPLE 1

(1) 500 g of an aqueous solution of alkali hydrolysed wheat protein (20% by weight) having a molecular weight (weight average) of 80,000 Daltons and 688 g of water were mixed in a beaker. 2.4 g of 25% sodium hydroxide was added to increase the pH to 8. The liquor was transferred to a flange flask which was fitted with a condenser and sealed. 303 g of 1-vinyl-2-pyrrolidone were added. The flask was then transferred to a water bath where it was heated to 70° C. A solution of 19.7 g of V50 initiator (azobis(amidinopropane)dihydrochloride) in 180 g of water was prepared, and gradually added to the flask over 1 hour. Once the addition was complete, the reaction was allowed to proceed for a further 3 hours. The pH was then lowered to 5.8 by the addition of hydrochloric acid. The resulting liquor was filtered to give a clear yellow aqueous solution containing approximately 25% by weight of hydrolysed wheat protein-PVP copolymer having a molecular weight (weight average) of 100,000 Daltons.

EXAMPLE 2

(2) The general process of Example 1 was repeated except that 750 g of an aqueous solution of enzyme hydrolysed wheat protein (20% by weight) having a molecular weight (weight average) of 2000 Daltons and 509 g of 1-vinyl-2-pyrrolidone were used. The resulting clear yellow aqueous solution contained approximately 20% by weight (2627 g) of hydrolysed wheat protein-PVP copolymer having a molecular weight (weight average) of 40,000 Daltons.

EXAMPLE 3

(3) The hydrolysed wheat protein-PVP copolymer solution produced in Example 2 was used to prepare an oil-in-water sunscreen emulsion having the following composition;

(4) TABLE-US-00002 % w/w Phase A. DC 245 Fluid (Cyclopentasiloxane) 8.0 CRODAMOL ™ OP (Ethylhexyl Palmitate (ex Croda)) 5.0 DC 2502 Fluid (Cetyl Dimethicone) 2.0 ARLAMOL ™ HD (Isohexadecane (ex Croda)) 2.5 CRODAMOL ™ AB (C12-15 Alkyl Benzoate (ex Croda)) 2.5 TIOVEIL ™ 50 FIN (C12-15 Alkyl Benzoate (&) 10.0 Titanium Dioxide (&) Polyhydroxystearic Acid (&) Aluminium Stearate (&) Alumina (ex Croda)) Phase B. Water qs ARLATONE ™ 2121 (Sorbitan Stearate (&) 4.5 Sucrose Cocoate (ex Croda)) Keltrol RD (Xanthan Gum) 0.2 Veegum Ultra (Magnesium Aluminium Silicate) 0.8 Rewoderm S1333 (Disodium Ricinoleamido 0.2 MEA-Sulfosuccinate) D-Panthenol 0.8 Propylene Glycol 4.0 Phase C. Hydrolysed Wheat Protein-PVP Copolymer 2.0 produced in Example 2 Phenonip 0.4

(5) Procedure

(6) 1. Arlatone™ 2121 and water were mixed together and heated to 80° C. until fully dispersed.

(7) 2. The remaining aqueous Phase B ingredients were added whilst maintaining temperature at 80° C.

(8) 3. The oil Phase A ingredients were mixed together and heated to 75-80° C.

(9) 4. Phase A was added to Phase B with intensive stirring.

(10) 5. The mixture was homogenised for 2 minutes.

(11) 6. The mixture was stirred and cooled to room temperature, with the Phase C ingredients being added below 40° C.

(12) The sunscreen product had an in vitro SPF value of 14.5, compared to 8.8 for the same formulation containing no hydrolysed wheat protein-PVP. This is a 60.7% increase in the SPF value of the formulation.

EXAMPLE 4

(13) The hydrolysed wheat protein-PVP copolymer solutions produced in Examples 1 and 2 were used to prepare an oil-in-water sunscreen emulsions having the following composition;

(14) TABLE-US-00003 % w/w Phase A. PRISORINE ™ 2039 (Isopropyl Isostearate (ex Croda)) 4.0 CRODAMOL ™ OP (Ethylhexyl Palmitate (ex Croda)) 1.9 ARLAMOL ™ HD (Isohexadecane (ex Croda)) 7.0 PRIPURE ™ 3759 (Squalane (ex Croda)) 8.0 SOLAVEIL ™ CT-100 (C12-15 Alkyl Benzoate (&) 12.5 Titanium Dioxide (&) Aluminium Stearate (&) Polyhydroxystearic Acid (&) Alumina (ex Croda)) Phase B. Water qs ARLATONE ™ 2121 (Sorbitan Stearate (&) 4.5 Sucrose Cocoate (ex Croda)) Keltrol RD (Xanthan Gum) 0.2 Veegum Ultra (Magnesium Aluminium Silicate) 0.8 Rewoderm S1333 (Disodium Ricinoleamido 0.2 MEA-Sulfosuccinate) D-Panthenol 0.8 Propylene Glycol 4.0 Phase C. Hydrolysed Wheat Protein-PVP Copolymer 2.0 produced in Examples 1 or 2 Phenonip 0.4

(15) The sunscreen products were produced using a similar procedure as described in Example 3. The in vitro SPF values for the compositions containing the hydrolysed wheat protein-PVP were 24.3 (for Example 1 material) and 23.2 (for Example 2 material), compared to 14.2 for the same formulation containing no hydrolysed wheat protein-PVP. These are 71.1% (Example 1) and 63.4% (Example 2) increases in the SPF value of the formulation.

EXAMPLE 5

(16) The hydrolysed wheat protein-PVP coolymer solution produced in Example 2 was used to prepare an oil-in-water sunscreen emulsion having the following composition;

(17) TABLE-US-00004 % w/w Phase A. ARLACEL ™ 165 FL (Glyceryl Stearate (&) 6.0 PEG-100 Stearate (ex Croda)) SPAN ™ 60 (Sorbitan Stearate (ex Croda)) 0.5 TWEEN ™ 60V (Polysorbate 60 (ex Croda)) 0.9 CRODACOL ™ S95 EP (Cetearyl Alcohol (ex Croda)) 1.0 Light Mineral Oil 8.0 Dow Corning 200 Fluid (350 cst) 2.0 CRODAMOL ™ OP (Ethylhexyl Palmitate (ex Croda)) 5.0 Escalol 557 (Ethylhexyl Methoxycinnamate (ex ISP) 5.0 Tinosorb S (Bis-Ethylhexyloxyphenol Methoxyphenyl 2.0 Triazine (ex Ciba) Phase B. Water qs Keltrol RD (Xanthan Gum) 0.1 Propylene Glycol 4.0 Phase C. Hydrolysed Wheat Protein-PVP Copolymer 2.0 produced in Example 2 Germaben II 1.0

(18) The sunscreen product was produced using a similar procedure as described in Example 3, and had an in vitro SPF value of 26.9, compared to 18.0 for the same formulation containing no hydrolysed wheat protein-PVP. This is a 49.4% increase in the SPF value of the formulation.

EXAMPLE 6

(19) The hydrolysed wheat protein-PVP coolymer solution produced in Example 2 was used to prepare a low viscosity sprayable emulsion having the following composition;

(20) TABLE-US-00005 % w/w Phase A. ARLACEL ™ 165 FL (Glyceryl Stearate (&) 1.5 PEG-100 Stearate (ex Croda)) SPAN ™ 60 (Sorbitan Stearate (ex Croda)) 1.0 ARLAMOL ™ HD (Isohexadecane (ex Croda)) 1.5 CRODAMOL ™ AB (C 12-15 Alkyl Benzoate (ex Croda)) 3.0 CRODAMOL ™ OC (Ethylhexyl Cocoate) 3.0 Dow Corning 245 Fluid (Cyclopentasiloxane) 2.25 Escalol 557 (Ethylhexyl Methoxycinnamate (ex ISP)) 6.0 Eusolex OCR (Octocrylene (ex Merck)) 6.0 Parsol 1789 (Butyl Methoxydibenzoylmethane, ex DSM)) 4.0 Titriplex III (Disodium EDTA) 0.1 Phase B. Water qs Keltrol RD (Xanthan Gum) 0.1 Veegum Ultra (Magnesium Aluminium Silicate ) 0.4 CRODAFOS ™ MCK (Potassium Cetyl Phosphate, 3.0 ex Croda) CRODEROL ™ GV9000 (Glycerin, ex Croda) 3.0 SOLAVEIL ™ CT-10W (Aqua (and) Titanium Dioxide 12.5 (and) Isodeceth-6 (and) Oleth-10 (and) Aluminum Stearate (and) Alumina (and) Simethicone, ex Croda) Phase C. Hydrolysed Wheat Protein-PVP Copolymer 2.0 produced in Example 2 Preservative qs

(21) Procedure 1. Keltrol RD and Veegum Ulta were dispersed into the water, the remaining water Phase B ingredients were added, and the mixture heated to 75-80° C. 2. Solaveil CT-10W was added to water Phase B with stirring, whist maintaining temperature. 3. Oil Phase A ingredients were mixed together and heated to 75-80° C. 4. Phase A was added to Phase B with stirring, and homogenised for 1 minute. 5. The mixture was stirred and cooled to room temperature, with the Phase C ingredients being added below 40° C.

(22) The sunscreen product had an in vivo SPF value (measured by proDERM, Germany) of 56, compared to 41.6 for the same formulation containing no hydrolysed wheat protein-PVP. This is a 34.6% increase in the SPF value of the formulation.

(23) The above examples illustrate the improved properties of a composition according to the present invention.