Journal of Pharmaceutical and Biomedical Analysis 22 (2000) 393–402 Short communication LC analysis of benzophenone-3 in pigskin and in saline solution Application to determination of in vitro skin penetration C. Fernandez a , G. Marti-Mestres c, *, J.P. Mestres b , H. Maillols c a Departmento de Farmacia Galenica, Facultad de Farmacia, Uniersidad de los Andes, Merida, Venezuela b Laboratoire de Chimie Analytique, Faculte ´ de Pharmacie -Uniersite ´ de Montpellier I, 34060 Montpellier, France c Laboratoire de Technique Pharmaceutique Industrielle, Faculte ´ de Pharmacie -Uniersite ´ de Montpellier I, 34060 Montpellier, France Received 16 January 1999; received in revised form 20 October 1999; accepted 27 November 1999 Keywords: Oxybenzone; Liquid chromatography; Pigskin; SPE-cartridges; Percutaneous absorption; Franz-type diffusion cell www.elsevier.com/locate/jpba 1. Introduction The use of sunscreens has increased with aware- ness of the detrimental effects (erythema, skin cancers) of UV light on human skin. In Europe sunscreens are classified as cosmetics, whereas in the USA they are OTC drugs. When a high sun protection factor in sunscreens is desired, ben- zophenone derivatives, most notably benzophe- none-3 or oxybenzone, are usually employed. Oxybenzone is currently used in many cosmetic formulations on the market, such as lipcares, sun- screen lotions or emulsions, shampoo and hair sprays. The efficacy of a sunscreen formulation depends on low penetration profiles and high photoprotection. These characteristics are impor- tant for cosmetic sunscreen safety. Sunscreens are applied repeatedly to exposed skin over a large surface area — approximately 1.8 m 2 for a 70-kg adult [1] There is little but recently published data describing their permeation through the animal, human skins or synthetic membrane and it is important to know how much penetrates. In these studies, preferentially formulations (emulsions: oil in water or water in oil, gel and lotions) were investigated in vivo or in vitro [2–5]. These prepa- rations contained a combination of various ingre- dients and some of them are established absorption enhancers (ethanol, sodium lauryl sul- fate, Tween 20, fatty alcohols) [6,7] and in these cases it is difficult to generalize findings from one to all preparations. The vehicle used is a factor influencing percutaneous absorption: it may en- hance or block the movement of the UV-filter * Corresponding author. Tel.: +33-4-67635431; fax: +33- 4-67048874. E-mail address: gmestres@ww3.pharma.univ-montpl.fr (G. Marti-Mestres) 0731-7085/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0731-7085(99)00277-0