Potential of nanoparticulate carriers for improved drug delivery via skin

Skin as a delivery route for drugs has attracted a great attention in recent decades as it avoids many of the limitations of oral and parenteral administration. However, the excellent barrier property of skin is a major obstacle in the effective transport of drugs through this route. The topmost layer of skin, the “stratum corneum” is the tightest one and is responsible for most of the resistance offered. This necessitates breaching the resistance of the stratum corneum reversibly and transiently in order to achieve a therapeutically meaningful level in systemic circulation or local skin. In last few decades, a number of approaches have been developed to improve the limited drug permeability through stratum corneum. One promising approach is the use of nanoparticulate carriers as they not only facilitate drug delivery across skin but also avoid the drawbacks of conventional skin formulations. This review focuses on nanoparticulate carriers including conventional liposomes, deformable liposomes, ethosomes, niosomes and lipid nanoparticles developed for topical and transdermal drug delivery. A special emphasis is placed on their composition, structure, mechanism of penetration and recent application. The presented data demonstrate the potential of these nanoparticulate carriers for dermal and transdermal delivery.