Drug Delivery Systems Using Immobilized Intact Liposomes: A Comparative and Critical Review

Liposomes sustain considerable interest to develop ways to fabricate drug delivery systems that would provide a good release without inducing any systemic reactions into the host. However, in many cases, liposomes injected into the blood stream are rapidly cleared from the system and only a fraction reaches the target site even when poly(ethylene glycol) (PEG)-coated liposomes are used. Composite drug delivery systems with liposomes i.e., liposomes linked to other substrates can be good candidates for certain type of drug release to achieve a localised treatment. This paper reviews the fundamental phenomena of the interactions between liposomes and solid substrates. Then, we address various techniques that have been used to immobilize intact liposomes onto and into different substrates. Finally, properties of liposomes used as drug delivery systems are briefly reviewed.