Silicones' Benefits in Antiaging Skin Care

By: Michael S. Starch, Dow Corning Corp.

Posted: November 13, 2008

page 5 of 5

One of the simplest delivery systems that can effectively protect antiaging actives is an anhydrous formulation. This is because water and chemicals contained in the water (acids, bases, dissolved oxygen, and metal ions) are often responsible for the degradation of the actives. Although this issue is eliminated by removing water from the formulation, other problems are created. A formulation consisting entirely of oils and oil-soluble ingredients is usually perceived as greasy or oily by the consumer. Another problem is that most thickening agents used to control the consistency of the formulation must be used with water. So the challenge in an anhydrous formulation is to improve aesthetics and thicken the formulation so it is not too thin and does not separate over time.

Silicone fluids offer greatly improved aesthetics, and silicone elastomers provide thickening while further improving aesthetics. Anhydrous skin treatment products based on silicones often are sold as small gelatin capsules that provide a single application when the capsule is broken. The protective effect of a silicone elastomer delivery system for certain actives that are soluble in silicone (e.g., retinyl palmitate) has been shown for conventional water-based formulations. The active is first combined with cyclomethicone and silicone elastomers, and this mixture is emulsified into the formulation. The affinity between the active and the silicone is apparently enough to keep the active in the silicone droplets and protected from degradation.

Summary
The term silicone represents a large family of polymers that range from low viscosity fluids, to viscous gums, to cross-linked elastomers and hard resins. Their unique chemical and physical properties have made silicones important ingredients in antiaging skin care products. Although perhaps best known for their aesthetic properties, these versatile materials improve the performance of many cosmetics, sunscreens and skin treatment products. The help deliver pigments and other particles to the skin, enhance protection by sunscreens and improve the stability of antiaging ingredients.

-Michael S. Starch
Personal Care Industry Scientist, Dow Corning Corp.
On behalf of the Silicones Environmental, Health and Safety Council of North America