Microemulsions for Sprayable Delivery and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: March 30, 2010, from the April 2010 issue of Cosmetics & Toiletries.

This month’s survey of recent patent and research literature describes moneymaking ideas for personal care product development, including fish DNA fragments for antiwrinkle skin care, soy peptides in cosmeceuticals, improvements in the efficacy of DHA, organo-sulfur compounds for skin lightening, and silicone foaming and detergency, among others.

Skin and Skin Care
Inhibiting melanin with thiazolamine: Shiseido Company Ltd. has disclosed thiazolamine derivatives or oxazolamine derivatives with melanin production-inhibitory activities.¹ Also disclosed are skin lightening cosmetics containing the compounds; for example, 4,5-dihydro-4,4-dimethyl-N-phenyl-2-thiazolamine was prepared and tested in vitro for melanin production-inhibiting activities.

Soy peptides in cosmeceuticals: Sekine et al. have published² on the production and skin permeation of soy derived peptides (SP). The effects of SP on type I collagen were evaluated to examine their potential for cosmeceuticals using the enzyme-linked immunosorbent assay (ELISA). A marked increase in type I collagen with SP application and a further increase with the simultaneous application of magnesium ascorbyl phosphate (VC-PMg) were shown. These effects were dependent upon the application concentration of the SP.

Also, amino acids such as glutamine and glutamic acid (GLU) entrapped in SP were found to easily permeate the skin, whereas the peptides GLU-GLU and GLU-GLU-GLU seldom permeated. However, an adjustment of the pH to that of amino acids and/or addition of l-menthol markedly increased the skin permeation of SP.

Picardin/oxybenzone interaction: Gu et al. have disclosed the in vitro permeation characterization of the repellent active picaridin and the sunscreen active oxybenzone.³ The authors performed a series of in vitro diffusion studies to evaluate the transmembrane permeation of picaridin and oxybenzone across human epidermis and a poly(dimethylsiloxane) (PDMS) membrane. The permeation of picaridin and oxybenzone across human epidermis was suppressed when both active ingredients were used concurrently. Increasing concentrations of the test compounds further reduced the permeation percentage of picaridin and oxybenzone.