Technically Speaking: UV Protection for Sensitive Skin

By: Charles Fox, Independent Consultant

Posted: February 1, 2007, from the February 2007 issue of Cosmetics & Toiletries.

Skin and Skin Care
Peptides for collagen, hyaluronic acid production: Rohto Pharmaceutical Co. Ltd. describes peptides that increase collagen or hyaluronic acid production. The invention discloses a peptide having a specified amino acid sequence, or derivative or salt thereof, and relates to a composition containing the peptide or the like, a method of using the peptide or the like, use of peptide or the like, and a polynucleotide encoding the peptide or the like. The peptide of the invention can be used for enhancing production of at least one member selected from collagen and hyaluronic acid in a cell.

Surfactant stabilization of hydroquinone: N. Iimura et al. report on the development of new whitening agents using hydroquinone stabilized by the formation of complexes with surfactants. In addition, they report on their evaluation for melanogenesis inhibition and skin stimulus.

Hydroquinone is well-known for skin depigmentation since it has been used clinically to inhibit melanogenesis. However, hydroquinone easily changes its structure when exposed to light, oxygen or heat. As a result, its color becomes brown or black. Iimura et al. have found that hydroquinone forms complexes with a variety of surfactant molecules. When a complex is formed, hydroquinone is stabilized without discoloration.

X-ray crystal structure analysis of the complexes revealed that the hydroquinone molecule becomes closely packed and covered with the surfactant molecules in the crystalline lattice. Among the complexes, a complex between hydroquinone and benzyl-hexadecyl-dimethylammonium chloride was examined in detail to establish its skin stimulus and safety. Moreover, the melanogenesis inhibitory effect was evaluated clinically. In every examination, the complex showed a good indication for the whitening agent.

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