Preparation of optimized Naproxen nano liposomes using response surface methodology

Abstract

The aim of this study was to prepare and optimize a liposomal delivery system for Naproxen (NPX), a practically water insoluble drug. NPX liposomes, which were consisted of cholesterol (CH) and phosphatidylcholine (PC) in different molar ratios, were prepared by modified ethanol injection method and optimized employing response surface methodology (RSM). Proportion of PC:CH and total lipid:drug ratio were selected as the independent variables while the particle size (PS), encapsulation efficiency percent (EE%) and drug release of the liposomes over 24 h (D24h) were considered as dependent variables. The effects of PC:CH and total lipid:drug ratios were studied and optimized to obtain the liposomal vesicles with desired quality. Graphical response surface and contour plots were also employed to understand the interaction of different variables. The optimum points for the variables were obtained from the optimization plot. The mean PS, EE% and D24h of NPX liposomes were about 178.11 nm, 53.14 and 46.62 % respectively. The results indicated that PC:CH and total lipids:drug ratios were the major contributing variables for EE% and D24h. However, only PC:CH ratio was the main contributing variable for PS. The optimum formulation of NPX liposomes, in which PC:CH ratio and lipids:drug ratio were 3.81 and 2.98 respectively, had high EE% (58 %) and D24h (>50 %) as well as appropriate PS (<162.4 nm). Ethanol injection method besides RSM, are simple, rapid and beneficial approaches for liposome preparation and optimization. آ© 2013 The Korean Society of Pharmaceutical Sciences and Technology.