Keywords: 
• Rhizoma Bletillae polysaccharide /
• paclitaxel /
• nanoparticles /
• pharmacokinetics

Abstract: Objective To establish a simple and sensitive method for the determination of plasma drug concentration in rats after intragastrical and intravenous administration of paclitaxel loaded nanoparticles and to evaluate its pharmacokinetic characteristics. Methods AgilentTC-C₁₈ column (250 mm×4.6 mm, 5 μm) was used for HPLC at the flow rate 1 ml/min with ketoconazole as internal standard and methanol acetonitrile water (45:20:35) as the mobile phase. The statistical moment method was applied to calculate the pharmacokinetic parameters and to evaluate pharmacokinetic characteristics. Results There was a good liner relationship (r=0.999 7) when rat blood concentration of Paclitaxel ranged from 0.5 to 20 μg/ml. The accuracy and precision were in line with the requirements of biological sample analysis. The t_1/2 were 3.86, 3.76, 3.35 and 2.62 h after intravenous injection of three lab-made paclitaxel nanoparticles and paclitaxel solution via rat tail vein. The t_1/2 were 5.28 and 3.72 h respectively after intragastrical administration of lab-made paclitaxel nanoparticles and paclitaxel suspension. Conclusion This method can be used for the pharmacokinetic study of paclitaxel nanoparticles in rats. The paclitaxel loaded nanoparticles exhibited significantly longer in vivo retention time than paclitaxel injection and paclitaxel suspension.