Combined use of phospholipid complexes and self-emulsifying microemulsions for improving the oral absorption of a BCS class IV compound, baicalin

The aim of this study was to develop a formulation to improve the oral absorption of baicalin (BA) by combining a phospholipid complex (PC) and self-emulsifying microemulsion drug delivery system (SMEDDS), termed BA PC SMEDDS. BA PC was prepared by a solvent evaporation method and evaluated by complexation percentage (CP). The physicochemical properties of BA PC were determined. The synergistic effect of PC and SMEDDS on permeation of BA was studied in vitro with Caco-2 cells and in situ with a single pass intestinal perfusion model. The improved bioavailability of BA in BA PC SMEDDS was confirmed in an in vivo rat model. The CP of BA PC reached 100% when the molar ratio of drug to phospholipid (PP) was > 1:1. The solubility of BA PC increased in both water and octanol, and the log Pow of BA PC was increased significantly. BA PC SMEDDS could be dispersed more evenly in water, compared to BA and BA PC. Both the Caco-2 cell uptake and single -pass intestinal perfusion models illustrated that transport of BA in BA PC was lower than that of free BA, while improved significantly in BA PC SMEDDS. The relative bioavailability of BA PC(1:2) SMEDDS was 220.37%. The combination system of PC and SMEDDS had a synergistic effect on improving the oral absorption of BA. (C) 2014 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.