This study is aimed to establish a method for the determination of baicalin,baicalin and purpurin in the plasma of rats after oral administration of Pudilan Xiaoyan Oral Liquid( PDL) by using liquid chromatography-mass spectrometry( LC-MS),analyze the pharmacokinetics of three components in rats,and investigate the effects of PDL on drug-metabolizing enzymes in rat liver. C18 column was used for liquid chromatography separation,with acetonitrile-water( containing 0. 2% formic acid) as the mobile phase for gradient elution. The mass spectrometry was detected by electrospray ion source( ESI) under multi-reaction monitoring mode( MRM),as well as positive and negative ion alternating mode. Plasma sample collection was performed by using an automatic blood collection meter for small animals. The pharmacokinetic parameters were calculated by Win Nonlin software. The total protein concentration of rat liver microsomes and the total enzyme content of CYP450 were determined by BCA method and spectrophotometry respectively. The methodological study in terms of linear range,recovery rate,precision and sample stability,was used to confirm that the LC-MS analysis method established in this experiment was simple,exclusive,accurate and reliable,and can meet the requirement of determining the content of baicalin,oroxindin and corynoline in plasma after PDL administration in rats. The drug-time curve showed that baicalin and oroxindin had a bimodal phenomenon,and the pharmacokinetic parameters indicated that baicalin,oroxindin and corynoline in PDL had certain drug-like properties. After 7 consecutive days of PDL administration,the rat liver coefficient,total liver microparticle protein and CYP450 enzyme content were increased,but there was no significant difference,indicating that PDL was less likely to develop drug-drug interaction based on CYP enzyme. The results of this experiment can provide reference for the research on in vivo efficacy and drug interaction of PDL as well as on its clinical application.
Keywords: Pudilan Xiaoyan Oral Liquid; baicalin; corynoline; liver enzyme; oroxindin; pharmacokinetics.