Physicochemical Properties of Silibinin-Phosphatidylcholine Complex and its Implications for Drug Formulations

Silibinin, an active constituent of silymarin possesses several medicinal properties. Although, the poor water solubility and less bioavailability restrict the clinical utility of silibinin, the complex of silibinin and phosphatidylcholine manifested outstanding biological activities in vivo. Thereby, the complex of silibinin was prepared with phosphatidylcholine (1:2, w/w) for better solubility and therapeutic efficacy and their physicochemical properties were analyzed. Thermal analysis, nuclear magnetic resonance and Fourier transform infrared spectroscopy data revealed that complex of silibinin with phosphatidylcholine improved binding efficiency of silibinin with non-covalent interactions. Kinetics of in vitro drug release with high performance liquid chromatography analysis showed that complex of silibinin-phosphatidylcholine released maximum 30 %-32 % silibinin into phosphate-buffered saline between 3 h to 6 h at pH 3 and 7 at 37°. Release profile of silibinin from silibinin-phosphatidylcholine complex in Swiss albino mice suggested that the complex increased silibinin concentration three times more in plasma samples of mice than individual silibinin treatment after 10 d. Furthermore, no significant changes were observed in body weight and diet consumption of mice throughout the study. Therefore, the study suggested that complex of silibinin-phosphatidylcholine improves the solubility and bioavailability of silibinin, which explains better efficacy and clinical potential of silibinin in its complex form against various disorders including cancer.