Microwave-triggered liposomal drug delivery: investigation of a model drug delivery system

Membrane permeability increases have been observed in liposomal vesicle systems during in vitro exposures to microwave, time-varying magnetic, and static magnetic fields. Cholesterol and other nonphospholipid components of the bilayer are currently being investigated as parameters that play an important role in permeability changes induced by these fields. To determine if liposomal vesicles are responsive to microwave fields under in vivo conditions, liposome vesicles were loaded with the drug gentamicin and used in drug delivery studies. Liposomes were place subcutaneously as a depot in the limb of a rat and the area treated with microwaves. Preliminary studies described here indicate that microwave fields enhance release of gentamicin, as measured by its appearance in the blood stream