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.

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Makeup Long wear, effect color cosmetics: Kosei Co., Ltd. has disclosed w/o emulsion makeup with special effects and that protects from easy removal.¹⁰ The makeup includes eye, highlighting and cheek color cosmetics containing lipophilic silicone surfactants with: a hydrophilic-lipophilic balance of 3–7, acrylic silicone graft copolymers, high viscosity oils, volatile silicone oils and powders. An example of an eye makeup is shown in Formula 2. The preparation imparted a transparent gloss and three-dimensional appearance to the skin, showing good application and retention on the skin for 8 hr.

Sunscreens
Ascorbic acid UVA filter: Merck GmbH has patented a UVA filter based on ascorbic acid derivatives and the use of the derivatives in hair and skin compositions.¹¹ The company prepared 2-(4-dihexylamino-2-hydroxybenzoyl)-benzoic acid ascorbyl ester from vitamin C and 2-(4-dihexylamino-2-hydroxybenzoyl)-benzoic acid. The derivative was formulated at 1% w/w in a UVA w/o emulsion, as shown in Formula 3.

Photostabilization of UV filters: An anonymous article reviewed the photostabilization of cosmetic UV filters before decomposition by UV irradiation.¹² Target UV filters were: butyl dibenzoylmethanea; cinnamate UV filters such as ethylhexyl methoxycinnamateb, octyl methoxycinnamate and octinoxate; or filters such as diethylamino hydroxybenzoyl hexyl benzoate. Photostabilizers included diphenylcyanoacrylate derivatives such as octocrylene, polycrylene, undecylcrylene dimethicone or naphthalates such as diethylhexyl 2,6 naphthalatec. Photo-unstable UV filters can be stabilized with antioxidants such as hydroxy dimethoxybenzyl malonate and hydroxy dimethoxybenzylidenmalonate. Formulations were given for w/o emulsions, hair care products, cosmetic foams, o/w emulsions and hydrodispersions for use as lotions/sprays.

Interesting Compositions and Ingredients
Silicone foaming and detergency: Shiseido Company Ltd. and Dow Corning Toray Co., Ltd. have disclosed silicone compounds for cleansing compositions with excellent foaming properties and detergency.¹³ The cleansing composition contains an organosiloxane derivative salt with the structure shown in either Eq. 1 or Eq. 2, and one or more anionic surfactants from a carboxylic acid salt group with an alkyl group of 10–20 carbon atoms including sulfuric acid salts, sulfonic acid salts and phosphoric acid salts.

R₁R₂R₃Si(CH₂)₂ACOOM     Eq. 1