Innovations in avoiding particle clearance from blood by Kupffer cells: cause for reflection.

Therapeutic applications of drug carrier systems following intravenous administration have been limited because of the pronounced tendency of these carriers to localize primarily in Kupffer cells. Recently, attempts have been made to design colloids and drug carrier systems that can be disguised as "self" and remain unrecognizable, at least to a certain extent, by the hepatic macrophages. This review is designed to provide a critical view on fundamentals, current progress, limitations, and future prospects of such engineered colloids and drug carrier systems for intravenous route of administration.