Release Kinetics of Novel Photosensitive Liposome for Triggered Delivery of Entrapped Drug

Abstract

Liposomes are nano-sized artificial vesicles of spherical shape composed of natural phospholipids and cholesterol. Doxil®, PEGylated liposomal formulation for the delivery of doxorubicin was the first product based on liposomes. Liposomes are the excellent nano-sized drug delivery system against many diseases like cancer. The basic problems associated with the delivery of drugs like anticancer drugs, are low volume of distribution and damage to normal tissues along with cancerous tissues. To eradicate non therapeutic and toxic effects associated with drugs like anticancer drugs, calcein (CAL) encapsulated reversed phase evaporation vesicles (REVs) carrying photoactive destabilization agent ketoprofen (KPF) in the lipid bilayer were formulated. Effect of UV radiation activation of liposomal membrane incorporated KPF on the destabilization of the liposome bilayer and the release of encapsulated CAL were investigated. Conventional and photosensitive liposomes of phosphatidylcholine (PC):Cholesterol (CHOL) in 5:1 molar ratio were formulated and investigated for size, CAL encapsulation efficiency (EE (%)) and Invitro release. Due to the incorporation of KPF in the photosensitive liposomal membrane approximately 4% increase in the EE (33%) in comparison to conventional liposomes (29%) was observed. Sizes of formulated liposomes were found between 200-400 nm. Exposure to UV radiation resulted in the release of CAL and in 10 hrs 97 % of entrapped CAL was released from photosensitive liposome and only 67% in case of conventional liposome in the same time duration. In this study, the in vitro drug release data from conventional liposomes as well as from photosensitive liposomes were fitted to various kinetic models and zero order release was found to be the mechanism of action. It was revealed from present study that this formulation could be considered as an ideal nano-sized system for triggered delivery of drugs like anticancer agents.