Skin Deposition

With the remarkable interest in the development of innovative pharmaceutical products, suitable methods need to be established to evaluate the fundamental physicochemical parameters required in pre-formulation studies. In the case of topical formulations, for which the drug is intended to act directly on the skin, evaluation of the drug deposition in the different skin layers is critical to establish dermal bioavailability and thereby make an approximation of the effectiveness.

Methodology

Skin deposition or retention experiments are performed ex-vivo using Franz diffusion cells and rat skin. The tested formulation is typically added to the donor compartment and incubated with the skin for a predetermined interval. At the end of the experiment, skin is removed and separated into the three different layers, namely the stratum corneum, epidermis and dermis. Each layer will be extracted with the suitable method and drug concentration will be determined in each individual layer.