Clinically-Proven Liposome-Based Drug Delivery: Formulation, Characterization and Therapeutic Efficacy

aqueous or lipid phases of liposomes with various sizes, compositions and other characteristics by different preparation techniques. An ideal method of liposome formulation is preparing liposome with high entrapment efficiency, narrow particle size distribution and long term stability. Numbers of techniques have been reported for preparation of liposomes such as Bangham method, the detergent depletion method, the ether/ethanol injection method, the reverse phase evaporation and the emulsion method The majority of liposome preparation methods require using organic solvents to dissolve lipids but these organic solvents are harmful to the environment and human body. Recently, some alternative methods including dense gas and supercritical fluid techniques have been introduced for liposome preparation without using any organic solvent Despite the clear advantages of dense gas or supercritical fluid liposome production, there are also problems with the known processes for liposome formation. The dense gas or supercritical fluid processes generally require elevated pressures of at least 1,000 psi and the conditions commonly used are 3000-4500 psi and temperatures of 60C for liposome production. For drug encapsulation, both antisolvent methods successfully encapsulated low molecular weight drugs such as paclitaxel, camptothecin and betulinic acid in liposomes However, high temperature, pressure, and shearing forces presenting in liposome processing condition with dense gas or supercritical fluid potentially denature high molecular weight drugs, such as peptides or proteins and result low production and encapsulation efficiency Physicochemical properties of liposomal formulations, including size, membrane lamellarity, surface charge, permeability, and encapsulation volume, are depending on the lipid composition (cationic, anionic, and neutral lipid species). The major function of liposome preparation