The use of scintigraphic imaging as a tool in the development of liposome formulations

Scintigraphic imaging is a valuable tool that can be used during the development of liposome-based therapeutic agents. It provides the ability to non-invasively track and quantitate the distribution of liposomes in the body. This review article provides a general overview of the methods involved in producing scintigraphic images as well as methods of radiolabeling liposomes. Liposomes labeled with technetium-99m ((99m)Tc) are particularly useful for scintigraphic imaging due to the physical characteristics of (99m)Tc, which provides a high quality image. Examples of how scintigraphic imaging studies have contributed to the development of a variety of liposome-based formulations are covered in this article. These liposome formulations include long-circulating liposome-based oxygen carriers, liposome-based anti-cancer drugs, liposomes encapsulating antibiotics and anti-fungals, and liposomes targeted to lymph nodes. Studies using scintigraphic imaging for the investigation of immune responses to liposomes are also discussed. These examples demonstrate the usefulness of scintigraphic imaging for the development of novel liposome formulations.