LC analysis of benzophenone-3: II application to determination of 'in vitro' and 'in vivo' skin penetration from solvents, coarse and submicron emulsions

The aim of this study was to determine the skin penetration of benzophenone -3 in vitro and in vivo in order to investigate a possible influence of for mulation. Six different vehicles, three solvents and three different emulsi on types were evaluated in vitro and in vivo. Each vehicle was applied to t he skin model at 2 mg cm(-2). First, histological studies on ear pigskin an d human skin were evaluated. In vitro measurements were performed with stat ic diffusion cells using pigskin at 1, 2, 4, and 8-h. In vivo, benzophenone -3 concentration in stratum corneum was evaluated by the stripping method a fter 30-min application on forearm of volunteers. It was shown that ear pig skin and human skin appear similar and in both experiments significant diff erences between vehicles were noticed. The six vehicles could be ranked in the same order of benzophenone-3 skin concentration. At 8-h, the highest co ncentration of benzophenone-3 in skin was obtained with propylene glycol, a nd O/W submicron emulsion. On the contrary, the two oily solvents, W/O emul sion and O/W coarse emulsion restrain the concentration of this UV-filter i n the skin. At each time, permeability in vitro and in vivo were well corre lated. Low concentrations were measured in the receptor fluid suggesting th at percutaneous absorption of this UV-filter across the skin would be minim al. The in vitro and in vivo skin penetration capacity of benzophenone-3 fr om six vehicles was confirmed and quantified. A satisfactory relationship b etween binary in vitro and in vivo was established. (C) 2000 Elsevier Scien ce B.V. All rights reserved.