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Promoting Collagen with Glycerophospholipids and Other Topics: Literature Findings
By: Charles Fox, Independent Consultant
Posted: September 29, 2009, from the October 2009 issue of Cosmetics & Toiletries.
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Self-tanner composition: Beiersdorf AG has disclosed cosmetic or dermatological formulations of dihydroxyacetone; glycyrrhetic acid and/or glycyrrhizine; and optionally erythrulose in cosmetic preparations for self-tanning.12 An example is shown in Formula 1.
Validating sunscreen agents: Lee et al. have published on the determination and validation of six sunscreen agents in sun care products through ultra performance liquid chromatography (UPLC) and high performance liquid chromatography (HPLC).13 Methylene bis-benzotriazolyl tetra-me butylphenol and bis-ethylhexyloxy phenol methoxyphenyl triazine are sunscreen agents that have hydrophobic behaviors in common. They typically are not assayed with the sunscreen agents ethylhexyl methoxycinnamate, isoamyl p-methoxycinnamate, ethylhexyl salicylate or ethylhexyl triazone, since these materials have hydrophilic behaviors in a single chromatographic run. For this reason, products containing methylene bis-benzotriazolyl tetra-me butylphenol and bis-ethylhexyloxy phenol methoxyphenyl triazine require more time to assay. Therefore, the development of a rapid, selective and reproducible determination method for the simultaneous examination of methylene bis-benzotriazolyl tetra-me butylphenol and bis-ethylhexyloxy phenol methoxyphenyl triazine with hydrophilic sunscreen agents would be beneficial to reduce the examination time required and to improve the quality control of sun care products.
In this paper, an HPLC and UPLC system is used to examine the sunscreen agents. Several evaluations of mixtures of eluents and columns were obtained for the optimal condition of separation. In HPLC, the optimal peak resolution was obtained through ethanol-water gradient elution and a 75-mm C18 column with a 3.5-mum-sized particle on a flow rate of 1.0 mL/min. In UPLC, the most distinctive peak resolution was obtained through methanol-water gradient elution and a 50-mm C18 column with a 1.7-mum-sized particle on a flow rate 0.4 mL/min. Both of these chromatographic determination methods could be used to examine six types of sunscreen agents without any interference from other product excipients in the agents. The proposed determination methods were validated for specificity, linearity, repeatability, system stability, intermediate precision and accuracy. Consequently, HPLC and UPLC methods could be used as rapid, selective and proper applications to assay sunscreen agents in sun care products.
Solid powder cosmetics: Tokiwa Corp. and Nippon Menard Cosmetic Co., Ltd. have disclosed compression-molded solid powder cosmetics with excellent impact resistance and spreadability.14 The cosmetics, useful for makeups, contain ≥ 30% w/w inorganic powders selected from mica, titanate mica and their surface-treated products; 0.2-4.0% w/w candelilla wax; and 0.5–4.0% w/w glycerin tris(caprylate/caprate). An eye color containing 27.68% w/w micac, 11% titanate micad, 0.2% candelilla wax and 2.0% w/w glycerin tris(caprylate/caprate)e showed uniform spreadability, a nonsticky feel, a moist feel on skin, and no cracking or peeling after falling.
Copolymers for adhesion in mascara: Pias Corp. has disclosed eyelash cosmetics containing urethane acrylate copolymers with excellent adhesion properties.15 The cosmetics contain the copolymers from methyl methacrylate, methacrylic acid and/or acrylic acid, urethane acrylates and optionally polyacrylic acid salts, alkali agents, water-dispersible film-forming agents, water-soluble polymers, fatty acids, nonionic surfactants, oil phase-forming agents, fibers and colorants. An example of a mascara is shown in Formula 2.