Preparation and Evaluation of Acyclovir Liposomes by Two Techniques: A Comparative Study

The aim of this study was to prepare liposomes of acyclovir (ACY) by thin layer evaporation (TLE) and reverse phase evaporation (REV) methods. Twenty-seven batches of liposomes from each method were prepared using technique of three variables at three levels (33) factorial design. Drug/Lipid (molar ratio), hydration volume and hydration time were considered three independent variables in TLE method while that of Drug/Lipid (molar ratio), organic phase volume and aqueous phase volume in REV method. Liposomes, obtained by TLE method (TLEs) and REV method (REVs) were evaluated for geometric mean diameter, and percent drug entrapment (PDE). REVs of 3.5(2.3) µm with 77.2% and of 3.4(2.2) µm with 71.1% drug entrapment was obtained with Drug/PC/CHOL (in molar ratio) of 1:4:0.5 and 1:2:0.5 respectively while TLEs of 4.3(1.7) µm with 79.5% drug entrapment was obtained with Drug/PC/CHOL (in molar ratio) of 1:20:10. In vitro studies were conducted to compare drug diffusion pattern across the human cadaver skin (HCS) of promising batches of TLEs and REVs. A significantly low (p