Water-soluble UV Filters and Other Topics

By: Charles Fox, Independent Consultant

Posted: January 30, 2009, from the February 2009 issue of Cosmetics & Toiletries.

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Skin brightener: Shuomingshu also discloses the use of N-acetyl-D-glucosamine as a skin brightener in cosmetics.⁵ N-acetyl-D-glucosamine inhibits tyrosinase activity, melanocyte proliferation, melanin formation, and tyrosinase protein and gene expression to brighten the skin. Cosmetics containing N-acetyl-D-glucosamine have good brightening effect, low cost and irritation, and are said to avoid occurrence of contact dermatitis, exogenous ochronosis or skin allergy.

Shower oil: Beiersdorf AG discloses a new shower oil containing turbidity preventing agents.⁶ These shower oils are liquid at room temperature. They contain oil at 30–90% by weight, water at 0–1%, turbidity inhibitors at 3–10%, and foam-forming, oil-soluble surfactants at 3–50%. The shower oil can be packaged in a self-dissolving bag prepared from polyvinyl alcohol foil. An example of a shower oil is shown in Formula 2.

Protection for fragile lips: L’Oréal discloses the use of active agents to increase the ceramide content of the lips for protective benefits.⁷ Active agents include ceramide precursors such as 6-hydroxy-4-sphingenine. Additional active agents are ascorbic acid and its analogs. The composition of a lipstick for fragile lips is shown in Formula 3.

Hair and Hair Care
Hair growth promotion: Hwang et al. have published on in vivo hair growth promotion effects of cosmetic preparations containing hinokitiol-loaded poly(epsilon-caprolactone) nanocapsules.⁸ Nanocapsules containing hinokitiol (HKL) were prepared by an emulsion-diffusion method. In an emulsification step to prepare the nanocapsules, cetyltri- methylammonium chloride (CTAC) was employed as a cationic emulsifier, poly(epsilon-caprolactone) (PCL) was used as a wall material, and HKL dissolved in octyl salicylate (OS) was used as a core material.

The submicron-sized nanoparticle was observed on a transmission electron microscope. The size ranged 55–234 nm and the mean diameters were 223 nm, which were determined by a dynamic light scattering method. According to the results of pH-dependent microelectrophoresis, the absolute value of the surface potential of the nanocapsules was greater than 20 mV.