Preparation, Characterization and Pharmacokinetics in Vivo of Oxymatrine?Phospholipid Complex

Abstract

The aim of the present study was to prepare oxymatrine-phospholipid complex to enhance oral bioavailability of oxymatrine and to study its physicochemical properties and to compare the pharmacokinetic characteristics and bioavailability after oral administration of oxymatrine-phospholipid complex in rats. Using tetrahydrofuran as a reaction medium, oxymatrine and phospholipids were resolved into the medium, after the organic solvent was removed under vacuum condition, oxymatrine-phospholipid complex was formed. The new complex's physicochemi-cal properties including differential scanning calorimetry (DSC), X-ray diffraction (XRD), N-octanol/water Partition Coefficient were tested. The concentrations of oxymatrine after oral administration of oxymatrine-phos-pholipids complex and oxymatrine at different time in rats were determined by HPCE. The pharmacokinetic parameters were computed by software program 3p87. The data showed that oxymatrine and phospholipids in the oxymatrine-phospholipid complex were combined by non-covalent bond, not forming a new compound and the solu-bility of oxymatrine-phospholipid complex in n-octanol was effectively enhanced. The better hepatocytes perme-ability was obtained by the phospholipid complex. We found that mean plasma concentration-time curve of oxymatrine after oral administration of oxymatrine-phos-pholipid complex and oxymatrine in rats was both in accordance with open two-compartment model with first-order absorption. Pharmacokinetic parameters of oxymatrine ,physical mixture and the complex in rats were T max 1.71, 1.91and 2.17 h, C max 0.164,0.247 and 0.437 µg·ml-1 , AUC 0-∞ 2.87, 3.23 and 9.43µg·h·ml-1 , respectively. The bioavailability of oxymatrine in rats was increased remarkably after oral administration of oxymatrine-phos-pholipid complex comparing to oxymatrine and the physical mixture. This was mainly due to an impressive improvement of the lipophilic property of oxymatrine-phos-pholipid complex.