The use of scintigraphic imaging during liposome drug development

Liposomes, spherical lipid bilayers enclosing an aqueous space, have become an important class of drug carriers. This review describes the usefulness of scintigraphic imaging during the development of liposome-based drugs. This imaging modality is particularly helpful for tracking the distribution of liposomes in the body, monitoring the therapeutic responses following administration of liposome-based drugs, and investigating the physiological responses associated with liposome administration. Scintigraphy also can be used to monitor the therapeutic responses of patients given approved liposomal drugs. Several examples describing the potential of this imaging modality during both the preclinical formulation and clinical trial stages of liposomal drug development are included. Techniques for radiolabeling liposomes as well as methods for producing scintigraphic images are also described.