Biopharmaceutical assessment of topical drug formulations is widely carried out by using vertical diffusion cells (Franz type cell). Although Franz diffusion cell model is well designed for percutaneous absorption studies, the extent of drug penetration within the skin requires more adapted device. Recently, we have developed a new patented versatile, easy-to-use, and disposable diffusion cell called VitroPharma. In this study we have assessed the cutaneous bioavailability of caffeine as hydrophilic compound model using Franz diffusion cell and VitroPharma. The percutaneous absorption of caffeine assessed with Franz diffusion cell and VitroPharma was characterized by using (i) finite dose model and (ii) classical pharmacokinetic analysis. Furthermore, the follow-up of caffeine penetration within the skin was determined by sequential measurements of tissular drug concentration throughout the time of skin exposure with VitroPharma. However, classical experimental design using Franz diffusion cell involved unique determination of tissular concentration at the final point of skin exposure protocol. Finally, device equivalence between Franz diffusion cell and VitroPharma was claimed from percutaneous absorption data analysis. Concomitant assessment of dual penetration and permeation kinetics by using VitroPharma reinforced the understanding of skin drug delivery.
Keywords: Franz diffusion cell; VitroPharma; caffeine; permeability assay; porcine skin.