Enhanced oral bioavailability of salvianolic acid B by phospholipid complex loaded nanoparticles.

With a simple and feasible method, a salvianolic acid B-phospholipid complex was prepared to increase the absorption of salvianolic acid B in the gastrointestinal (GI) tract. Because the solubility of the complex in water was very poor, the complex was encapsulated into nanoparticles to facilitate its administration. The physicochemical properties of the complex were investigated by differential scanning calorimetry (DSC), infrared scanning, ultraviolet scanning and X-ray diffraction (XRD), and the solubility of salvianolic acid B and the complex in water or n-octanol was measured. The pharmacokinetic characteristics and bioavailability were compared after oral administration of salvianolic acid B (500 mg/kg) and the complex nanoparticles (450 mg/kg equivalent to salvianolic acid B). The results proved the drastic decrease in the solubility of salvianolic acid B in water after successful formation of the drug-phospholipid complex. After oral administration the peak plasma concentration (Cmax) of salvianolic acid B given by the complex nanoparticles was 3.4 microg/ml which was much higher than that of salvianolic acid B sample (Cmax = 0.9 microg/ml), with Tmax of 75 min, 45 min and AUC of 664, 257 microg/ml min, respectively. The relative bioavailability (F) reached 286%.