Elastic Liposomes for Topical and Transdermal Drug Delivery

Elastic liposomes have been developed and evaluated as novel topical and transdermal delivery systems. They share some similarities to conventional liposomes but their composition is designed to confer flexibility and elasticity in the lipid bilayer structure. Elastic liposomes are applied non-occluded to the skin and are reported to permeate through the stratum corneum lipid lamellar regions as a result of the hydration or osmotic force in the skin. They have been investigated as drug carriers for a range of small molecules, peptides, proteins, and vaccines, both in vitro and in vivo. Following topical application, structural changes in the stratum corneum have been identified and intact elastic liposomes visualized within the stratum corneum lipid lamellar regions, but evidence of intact liposomes in the deeper viable tissues is limited. The method by which they transport their drug payload into and through the skin has been investigated but remains an area of contention. This chapter provides an overview of the development, characterization, and evaluation of elastic liposomes for delivery into and via the skin.