Formulation and Evaluation of levofloxacin stealth liposome using different polymers

Levofloxacin is an antibacterial agent used to treat various urinary tract infection as well as pneumonia. Levofloxacin was formulated as liposome using soya lecithin and cholesterol by thin film hydration method. It is then formulated as stealth liposome to increase the efficacy and reduce the toxicity and target the organs RES and thus prolonging its circulation time thereby reducing clearance. Two polymers are used to prepare Levofloxacin as stealth liposome i.e., PEG and PVP and their effects are compared. The formulated liposomes and stealth liposomes were evaluated for various parameters like surface morphology, zeta potential, poly dispersity index, drug content, % drug encapsulation and invitro drug release. The optimized formulation (F2) containing minimum concentration of cholesterol showed moderate stability and good entrapment efficiency. The stealth liposomes showed more stability and sustained drug release for 24hr compared to conventional liposomes. The size of stealth liposomes was slightly enhanced compared to conventional liposomes due to the polymers forming thick surface layer on surface of the vesicles. When compared to conventional liposomes, stealth liposomes showed more zeta potential values due to the effect of PEG 4000 and PVP K30.The value of zeta potential showed that stealth liposomes had sufficient charge to inhibit aggregation of liposomes due to electric repulsion. The kinetic data analysis of formulations indicated that it fits to Higuchi model and follows zero order release kinetics. The mechanism of drug release from the stealth liposomes followed non-fickian diffusion. The stability studies of the optimized stealth liposome were subjected as per ICH guidelines.