Innovative silicone strategies to fight skin ageing

Transcription

1 Innovative silicone strategies to fight skin ageing M. Eeman 1, J.-L. Garaud 1, I. Van Reeth 2 1 Dow Corning Europe, S.A., Seneffe, Belgium 2 Dow Corning (Shanghai) Co. Ltd., Shanghai, China July 14 th, 2016

2 A growing need to protect skin from the ravages of air pollution Nowadays the skin is increasing assaulted as a result of the increasingly complexity of our living environment. Because of its critical location, the skin is continuously exposed not only to natural environmental stress factors, such as UV radiation, ozone and extreme weather conditions associated with climatic changes, but also to pollutants/aggressors of anthropic origin, such as cigarette smoke, diesel fuel exhaust, chemical agents, and mechanical abrasion. The damaging effect of pollution on skin has been reported in consumer magazines/blogs as well as in the scientific literature. 2

3 2 approaches Silicone film former for preventing the environmental stressors to reach skin surface. Silicone Elastomer matrix for improved stabilization and delivery of Vitamin C to enhance free radicals neutralization 3

4 PROTECTION AGAINST ENVIRONMENTAL STRESSORS 4

5 A range of silicone technologies Silicone Gums Silicone-Based Film-Formers Silicone Resins CH 3 CH 3 CH 3 CH 3 - Si - O - ( Si - O ) n - Si - CH 3 CH 3 CH 3 CH 3 Acrylbackbone Silicone Dendrimer Acrylates Silicone Resin Gums Me Me Me Si O Me Me Si O Si O Me Si Me Me O O Me Me Me Si Me Me Me O Me C 2 H 4 Si O Si O Si C 2 H 4 Si O Si Me Me O Me O Me Me Si Me Me Si Me C 2 H 4 Me Me Me Me Si O Si O Si Me Me O Me Me Si Me Me O CF 3 O HO-Si HO-Si Si-O-Si Si-O-Si Si-OH Si-O-Si Si-O-Si HO-Si Si-O-Si Si-OH Si-OH 5

6 Silicone film-formers Features/benefits: - Low surface tension: Very good spreading - Good adhesion to the skin: Long-lasting/rub-off resistance - High water repellency (> 100 ) - Good sebum repellency (~ 60 ) - Uniform and flexible film for comfort of wear - Non occlusive - Superior sensory - Can be delivered from several carriers including water 6

7 Protection against Particle adhesion Nature shows the way The leaves of the lotus plant (Nelumbo nucifera) remain free from particulate matter thanks to unique surface properties that combine to create a state of superhydrophobicity. Low surface energy Credit: Andrew H. Cannon A microroughened structure

8 Protection against Particle adhesion Method #1: Sprinkling method Furnace carbon black with average aggregate particle size < 0.5 microns and average particle size [5-75] nm 8

9 Protection against Particle adhesion Method #1: Results on collagen The addition of Silicone Dendrimer Acrylate Copolymer into a W/O emulsion reduces particulate adhesion. SEM Control W/O Emulsion SEM With Silicone Dendrimer Acrylate Copolymer Particulate adhesion Particulate adhesion High adhesion Low adhesion In-vitro testing on 60-micron coating on collagen (internal test). 9

10 Protection against Particle adhesion Method #1: Results on pig skin The addition of Silicone Dendrimer Acrylate Copolymer into a W/O emulsion reduces particulate adhesion. Control W/O Emulsion With Silicone Dendrimer Acrylate Copolymer Tested in triplicates 10

11 Protection against Particle adhesion Method #2: Spaying method EXPOSE TO CARBON BLACK Film exposed to carbon black suspended in air via a compressed air flow Furnace carbon black with average aggregate particle size < 0.5 microns and average particle size [5-75] nm 11

12 Protection against Particle adhesion Method #2: Results The addition of Silicone Dendrimer Acrylate Copolymer into a W/O emulsion reduces particulate adhesion. Control W/O Emulsion With Silicone Dendrimer Acrylate Copolymer Substrate: Collagen Substrate: Pig skin 12

13 Protection against Particle adhesion Method #3: In vivo method APPLY ON FOREARM EXPOSE TO CARBON BLACK EVALUATE PERFORMANCE 2 mg/cm 2 applied, 30 min drying time Sprinkling method Carbon black nano-size grade, mean particle size ~40nm 13

14 Protection against Particle adhesion Method #3: Results (in vivo) The addition of Silicone Dendrimer Acrylate Copolymer into a W/O emulsion reduces particulate adhesion. Control W/O Emulsion With Silicone Dendrimer Acrylate Copolymer Tested with 6 replicates. 14

15 IMPROVE STABILITY OF ACTIVES SENSITIVE TO OXIDATION Vitamin C ( Ascorbic Acid) 15

16 Improve stability of Vitamin C Development of an anhydrous delivery system to stabilize up to 10wt% pure Vitamin C in presence of glycerin Ingredients Emulsifier (PEG-10 Dimethicone, PEG/PPG-19/19 Dimethicone, etc.) 0-6 Wt% Carrier (Caprylyl Methicone, Isododecane) 0-20 Silicone Elastomer Powder or Blend (Dimethicone Crosspolymer, Dimethicone/Vinyl Dimethicone Crosspolymer, etc.) 4-30 dl-α-tocopheryl Acetate 0-1 L-Ascorbic Acid 1-10 Polyol (Glycerin, Propylene Glycol, Butylene Glycol, etc.)

17 Improve stability of Vitamin C Comparison with a commercial benchmark Day 0 / RT Day 3 / RT Day 7 / RT Day 28 / RT Day 28 / 50 C Commercial benchmark 5% Ascorbic Acid Anhydrous Si system 5% Ascorbic Acid Commercial benchmark composition: aqua, glycerin, cyclopentasiloxane, Ascorbic Acid (5 wt%), propylene glycol, nylon-12, sodium hydroxide, citric acid, PEG/PPG-18/18 dimethicone, propylparaben, acrylates copolymer, fragrance, disodium EDTA, methylparaben. 17

18 Delivery and efficiency of Vitamin C Over a 6h period, 10% of Vitamin C contained in the formulation applied on the skin surface penetrates into the skin. In the skin it is mainly distributed into the Stratum Corneum and the living epidermis. Absorption profiles through full-thickness pig skin tissues Blend glycerin/aa 5% AA Anhydrous silicone system 5% AA Commercial benchmark 5% AA Skin model: full-thickness pig skin samples mounted on Franz diffusion cells (6 replicates) Drug content: 5%. Applied dose: 7±1 mg/cm². Temperature: 32ºC 18

19 Inhibition of melanin synthesis, % (with control, untreated RHEm set at 0%) Delivery and efficiency of Vitamin C In vitro testing using melanocytes-containing pigmented reconstituted human epidermis resulted into a 34% inhibition of melanin synthesis *** 52% ** 47% Inhibition of melanin synthesis in pigmented reconstructed epidermis from day 7 to day 16 ** % ns 13% 19

20 Sensory possibilities Comparison to formulation A: Before absorption B C D E F G Without elastomer High viscosity emulsifier High volatile oil phase Wetness Spreadability Propylene glycol instead of glycerin Pure blend vitamin C / glycerin Commercial benchmark containing water Tackiness Absorbency After absorption Gloss Film residue Greasiness Smoothness Tackiness Slipperiness Powdery feel - * : 95%; ** : 99%; *** : 99.9% Si elastomer gels: absorption rate, gloss & greasiness of glycerin-rich formulations Si emulsifier: impact on formulation texture & spreading (viscosity 10 times higher for formulation C) Volatility of the oil phase: impact on sensory after absorption (gloss, film residue and greasiness ) Polyol nature: impact on sensory profile (tackiness ) after absorption Water: lighter sensory perception but at the expense of vitamin C stability Formulation A: Low Viscosity emulsifier and Silicone elastomer in medium volatility carrier. 20

21 Conclusions Original test methods were developed to evaluate the potential protection of silicone film-formers against particles and ozone. Silicone dendrimer acrylate copolymers form a flexible and comfortable barrier film at the skin surface allowing a preventive protection approach against environmental pollutants: By decreasing the adhesion of polluted particles (demonstrated in vitro and in vivo); By reducing the cutaneous damage (specifically skin inflammation) induced by pollutants such as ozone and cigarette smoke (demonstrated in vitro). An anhydrous silicone matrix combining silicone elastomer and emulsifier was shown to be an efficient carrier system for stabilizing and delivering Vitamin C through the skin to repair damage caused by pollution with improved sensory versus existing glycerin-based systems.

22 References J.-L. Garaud, A. Sieg, M. Le Meur, H. Baillet, I. Van Reeth, S. Massé; Silicones as innocuous materials to keep natural moisture balance and protect skin against particle pollution ; SOFW-Journal, 140, December 2014, pp M. Eeman; I. Van Reeth : Specialty Silicones Provide Long-Lasting Color and Unique Sensory Experience, Euro Cosmetics (7/8-2015), M. Eeman, I. Van Reeth: Silicone film formers An answer to skin care trends, Cosmma magazine (9/2015), M. Eeman, R. Bao, I. Van Reeth: Specialty silicones for skin lightening products, Personal Care Asia Pacific, Magazine, Nov 2014,

23 Commercial references from Dow Corning materials used in this work: INCI Name Trade name Function Isododecane (and) Acrylates/Polytrimethylsiloxymethacrylate Copolymer Dimethicone (and) Acrylates/Polytrimethylsiloxymethacrylate Copolymer Dow Corning FA-4002 ID Silicone Acrylate Dow Corning FA-4003 DM Silicone Acrylate Film-former Film-former PEG-10 Dimethicone PEG/PPG-19/19 Dimethicone (and) C13-16 Isopareffin (and) C10-13 Isoparaffin Dow Corning ES-5612 Formulation Aid Dow Corning BY Emulsifier Emulsifier Caprylyl Methicone Dow Corning FZ-3196 Carrier Dimethicone (and) Dimethicone Crosspolymer Dow Corning 9041 Elastomer Blend Dimethicone/Vinyl Dimethicone Crosspolymer (and) Silica Dow Corning 9701 Cosmetic Powder Sensory modifier Sensory modifier 23

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