Abstract
This study was concerned with whether drug-entrapping liposomes can be prepared by using lyophilized, empty dipalmitoylphosphatidylcholine (DPPC)-liposomes. It was found that drug-entrapping liposomes could be prepared by warming a mixture of lyophilized empty DPPC-liposomes and aqueous drug solution over the solid-liquid crystal phase-transition temperature (Tc), indicating that warming (>Tc) resealed the defect in the bilayer membranes after incorporation of the drug into the empty liposomes. The pharmaceutical potential of this new method was examined, and the results proved that drug-containing liposomes could be prepared readily or immediately before use, and with reproducibly high efficiency (40-70%) of entrapment.
