title: Surface recovery and stripping methods to quantify percutaneous absorption of caffeine in humans.
abstract: The percutaneous absorption of caffeine from two vehicles, an emulsion and an acetone solution, was quantified by in vivo techniques in humans. A surface recovery technique over a 6-h application and a stripping method after a 30-min application were performed on the volar aspect of the forearm on 12 volunteers. Caffeine was assessed by HPLC. Two phases were distinguished in the percutaneous absorption of caffeine: a higher filling up of the stratum corneum with the oil-in-water emulsion than with the acetone solution, which was then followed by a steady-state flux corresponding to the penetration in the living tissues. The permeability constants (Kp) with emulsion and acetone were 1.59 x 10(-4) and 9.53 x 10(-8) cm/h, respectively. The stripping method showed concentrations of caffeine in stratum corneum that were five times higher with emulsion (212 ng/cm2) than with acetone (37 ng/cm2). With acetone as a vehicle, approximately 40% of caffeine of the cornfield layer was found around the treated area. This sizeable lateral spread within the stratum corneum was not observed with the emulsion.
authors.affiliation: Service de Dermatologie, Hôpital St Jacques, Besancon, France.
authors.forename: O
authors.initials: O
authors.lastname: Chambin-Remoussenard
authors.forename: P
authors.initials: P
authors.lastname: Treffel
authors.forename: Y
authors.initials: Y
authors.lastname: Bechtel
authors.forename: P
authors.initials: P
authors.lastname: Agache
mesh_terms: D000328:Adult; D002110:Caffeine / Q000493:pharmacokinetics*; D004817:Epidermis / Q000378:metabolism; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D012869:Skin Absorption
chemical_list: D002110:Caffeine