Natural Hair Dyes, Self-tanning Solutions and Other Topics: Literature Findings

By: Charles Fox, Independent Consultant

Posted: October 30, 2009, from the November 2009 issue of Cosmetics & Toiletries.

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Biofunctional DHA derivatives for self-tanning: Merck Patent GmbH created biofunctional dihydroxyacetone derivatives for self-tanning preparations.¹⁶ The formulations may further contain sunscreens, vitamins, insect repellents, preservatives, etc. Dihydroxyacetone-o-ethyl acetate was synthesized from dihydroxyacetone and triethylorthoacetate in dioxane using (+/-)-camphor-10-sulfonic acid catalyst. An example of an o/w self-tanning cream is shown in Formula 7.

Raw Materials
Organopolysiloxanes as emulsifiers or dispersing agents: Evonik Goldschmidt disclosed the use of ester-modified polyether-free organopolysiloxanes as emulsifiers or dispersing agents in w/o, o/w and w/s cosmetic, pharmaceutical or cleaning formulations.¹⁷ Coco fatty acid was enzymatically esterified with allyloxyethanol and the product was reacted with glycerinmonoallylether and a polymethylsiloxane in the presence of a Karstedt catalyst. The obtained glycerinmonoallylether-, and allyloxyethanol coco fatty acid ester-modified polymethylsiloxane was formulated at 2.0% w/w in a cosmetic w/o emulsion along with 0.1% w/w hydrogenated castor oil, 0.1% w/w microcrystalline wax, 11.8% w/w liquid paraffin, 6.0% w/w ethylhexyl palmitate, 0.8% w/w sodium chloride, 3.1% w/w glycerin, 76% w/w water and 0.10% w/w 2-bromo-2-nitropropane-1,3-diol. Lipase inhibitors: Asahi Kasei Chemicals Corp. discussed lipase inhibitors containing water-soluble, beta-linked oligosaccharides in addition to disclosing cosmetic, (quasi) drug, or hair preparations containing the lipase inhibitors.¹⁸

Lipase inhibitors are useful to prevent or treat acne or body odor. They contain water-soluble carbohydrates comprising ≥ 2 beta-linked monosaccharides. An aqueos cellulose dispersion, prepared by grinding HCl hydrolyzates of dissolving pulp, was incubated with Trichoderma reesei-derived crude cellulase preparation at 55°C for 4 hr to give a composition containing 1.5% cellobiose.

The composition was filtered with an ultrafiltration membrane, treated with cation ion exchange resin and anion ion exchange resin for deionization, and vacuum-distilled at 70°C. The concentrate was gradually cooled at 10°C/hr, from 70°C to 5°C, and precipitated with ethanol. The precipitate was further processed to produce cellooligosaccharide powder containing 96.4% cellobiose and 0.8% additional cellooligosaccharides. The cellobiose-rich fraction inhibited Propionibacterium acnes lipase in a dose-dependent manner. A hair lotion containing the fraction imparted a refreshing feeling and smoothness to hair.

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