Enhancing the in vitro release of total flavonoids extract from Dracocephalum moldavuca composite phospholipid liposomes optimized by response surface methodology

Abstract

The present study was undertaken to optimize the preparation conditions of total flavonoids extract from Dracocephalum Moldavuca composite phospholipid liposome (TFDMCPL) by response surface methodology (RSM) and to investigate the in vitro release (IVR) of TFDMCPL. Method of ethanol injection was adopted to prepare TFDMCPL. The single factor experiments were used for the key experimental factors and their test range. Based on the single factor experiments, with encapsulation efficiency (EE) Size of TFDMCPL and polymey disperse index (PDI) as dependent variable, central composite design was adopted to optimize preparation technology by taking content of phospholipid and content of cholesterol as independent variables, fitting of various mathematical equations were performed using a statisitical software of Design-Expert 8.0.6. Preparation parameters were optimized through response surface plotted by optimum fitting equations, optimized procedure was validated through experimental preparation of TFDMCPL. Optimum preparation technology was as following: phospholipid 505mg and cholesterol 50mg. Under these condition, encapsulation efficiency was 90.2±1.2%, size of TFDMCPL was 115.6±4.3nm, PDI was 0.169±0.015 and Zeta potential was -15.38±0.5. These indicated that TFDMCPL with high entrapping efficiency and small particle size could be prepared by the ethanol injection method. And TFDMCPL were found to enhance the release of drugs more effectively than TFDM based on the in vitro model.