Release of benzimidazole and benzylidene camphor from topical sunscreen formulations.
Absorption of two ultraviolet (UV) filters was evaluated through a lipophilic synthetic membrane (Folioxane) and excised hairless rat skin using a flow-through diffusion cell. Folioxane membrane is an artificial skin used in the treatment of third-degree burns. Diffusion tests were performed with aqueous solutions and galenic formulations (one water-in-oil [W/O] emulsion and two oily gels). Analyses were achieved with high-performance liquid chromatography (HPLC) with UV detection at 295 nm. Diffusion kinetics of 17 beta estradiol, a reference compound, through rat skin, human skin, and Folioxane membrane were performed to validate the in vitro model. Phenylbenzimidazole and methylbenzylidene camphor in aqueous solutions were diffused at a regular rate through the Folioxane film. The release of phenylbenzimidazole was very slow, whereas the release of benzylidene camphor was more pronounced: a decrease of the quantity was observed in the donor compartment (30% at 6 hr and 93% after 72 hr). A significant flow of benzylidene camphor was also measured through excised skin of rat in the first 3 hr. The skin absorption was 38% over 72 hr. The W/O emulsion had low penetration of UV filter: 20% of the initial amount for Folioxane membrane and 0.4% for rat skin. In contrast, the penetration of two oily gels was identical: 28% on Folioxane membrane and 0.6% on rat skin. This study demonstrates the transcutaneous diffusion of two important classes of sunscreens through a lipophilic Folioxane membrane and through excised hairless rat skin. From the results, Folioxane membrane appears to be an alternative model for studying diffusion of topical molecules and as a tool for guiding formulation choices.
Aghazarian
V
V
Laboratoire de Pharmacie galénique et Cosmétologie, Faculté de Pharmacie, Marseille, France.
Tchiakpe
L
L
Reynier
J P
JP
Gayte-Sorbier
A
A
D000287:Administration, Topical; D000818:Animals; D001562:Benzimidazoles / Q000493:pharmacokinetics*; D001597:Benzylidene Compounds / Q000493:pharmacokinetics*; D002164:Camphor / Q000493:pharmacokinetics; D004058:Diffusion; D004655:Emulsions; D004958:Estradiol / Q000493:pharmacokinetics; D005782:Gels; D006801:Humans; D008567:Membranes, Artificial; D051381:Rats; D015203:Reproducibility of Results; D012869:Skin Absorption; D013473:Sunscreening Agents / Q000493:pharmacokinetics*
D001562:Benzimidazoles; D001597:Benzylidene Compounds; D004655:Emulsions; D005782:Gels; D008567:Membranes, Artificial; D013473:Sunscreening Agents; D004958:Estradiol; D002164:Camphor