Session Speaker

SECosomes for Delivery of siRNA into Cultured Primary Melanocytes and Ex Vivo Human Skin
B. Geusens, S. Braat, M. Stuart, S. De Smedt, N. Sanders, T. Prow, M. Roberts, M. Van Gele and J. Lambert
Belgium

The skin is an important route for drug delivery as it allows non-invasive application of therapeutics for systemic as well as for local treatment. However, the very efficient barrier properties of the skin impede the penetration of topically administrated therapeutics. Our aim is to develop a new type of lipid-based formulation for the delivery of siRNA in primary melanocyte cell cultures and human skin. We use siRNA to specifically block the expression of a Myosin Va exon F containing isoform that is physiologically involved in melanosome transport in human melanocytes. By modulating pigment transport we aim to develop new therapeutics for the treatment of (hyper)pigmentation. New formulations were prepared using DOTAP, cholesterol, sodium cholate and ethanol, and were called Surfactant-Ethanol-Cholesterol-osomes (SECosomes). After complexation with siRNA they were characterized in vitro and ex vivo. Their size, surface charge, morphology, deformability, transfection efficiency, stability and skin penetration capacity were investigated. Results show that this new type of carrier has ideal characteristics for siRNA incapsulation, in vitro siRNA delivery as well as creating a stable siRNA environment for at least 4 weeks. Moreover, their penetration capacity through ex vivo human skin and uptake by keratinocytes hold great promise for future topical applications.