Substantivity of sunscreens —in vitro evaluation of the transdermal permeation characteristics of some benzophenone derivatives |
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Authors: | D. MONTI M.F. SAETTONE M. CENTINI C. ANSELMI |
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Affiliation: | Laboratorio di Tecnologie Farmaceutiche-Biofarmacia, Universitàdi Pisa, Via Bonanno 6, I-56100 Pisa, Italy;Istituto di Chimica Organica, Universitàde Siena, Pian dei Mantellini 44, I-53100 Siena, Italy |
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Abstract: | The in vitro permeation through excised hairless mouse skin of a series of 4-O-(N, N-dimethylaminoalkyl)-benzophenones, non-quaternarized and quaternarized, and of two commercial benzophenone sunscreens, taken as reference compounds, was investigated. The aim of the study was to verify the skin penetration of the highly skin-substantive quaternary ammonium derivatives, in comparison with their parent, non-quaternarized compounds. While the quaternary derivatives proved unable to permeate the skin during the period of observation (45 h), their parent amine hydrochlorides and the reference sunscreens (2-hydroxy-4-methoxy-benzophenone-5-sulphonic acid and 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone 5,5'-sodium disulphonate), showed appreciable transdermal fluxes. These data indicate that the presence of a quaternary ammonium group in a molecule, besides inducing a high affinity for cutaneous keratin, may result in hindered or reduced transdermal (and possibly systemic) absorption. Both features may contribute in improving the safety of a cosmetic sunscreen. |
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Keywords: | unscreens benzophenone derivatives quaternary ammonium skin permeation in vitro hairless mouse skin skin substantivity |
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