Preface

The science and technology of liposomes as a delivery system for drugs and vaccines have evolved through a variety of phases that I have been privileged to witness from the very beginning. The initial observation (1) that exposure of phospholipids to excess water gives rise to lamellar structures that are able to sequester solutes led to the adoption of these structures (later to become known as liposomes) as a model for the study of cell membrane biophysics. Solute sequestration into liposomes prompted a few years later the development of the drug delivery concept (2,3) and, in 1970, animals were for the first time injected with active-containing liposomes (3,4). Subsequent work in the author’s laboratory and elsewhere worldwide on drug-and vaccinecontaining liposomes and their interaction with the biological milieu in vivo culminated in the licensing of a number of injectable liposome-based therapeutics and vaccines. The history of the evolution of liposomes from a structural curiosity in the 1960s to a multifaceted, powerful tool for transforming toxic or ineffective drugs into entities with improved pharmacological profiles today has been summarized elsewhere (5,6).