Development and Characterization of liposomal aerosols for improved delivery of etoposide to the lungs

Abstract

The present study deals with firstly at preparation, characterization and performance evaluation of Etoposide loaded
aerosolized liposomes for their selective presentation to lungs, for the treatment of lung cancer. Secondly, to
enhance the delivery of drug to the lungs via site specific targeting. Soya phosphatidyl choline and cholesterol based
liposomes were modified by coating them with mannose. The prepared formulations were characterized in vitro for
vesicle size distribution and percent drug entrapment. Aerosolization was done by air jet nebulizers. In-vitro airways
penetration efficiency of the liposomal aerosols was determined by percent dose reaching the peripheral airways; it
was recorded 1.4-1.6 times higher as compared to plain drug solution based aerosol. In-vivo tissue distribution
studies on albino rats suggested the preferential accumulation of mannose coated formulations in the lungs. Higher
lung drug concentration was recorded in case of ligand-anchored liposomal aerosols as compared to plain drug
solution and plain liposome based aerosols. The drug was estimated in the lung in high concentration even after 24
hr. The drug localization index calculated after 6 hr. was nearly 1.42-4.47 and 4.16 fold respectively for plain,
galactose and mannose coated liposomal aerosols as compared to plain drug solution based aerosols. These results
suggest that the ligand-anchored liposomal aerosols are not only effective in rapid attainment of high drug
concentration in lungs and also maintain the same over prolonged period of time.