兔血清中褪黑激素的HPLC测定及其药动学研究

 目的 建立褪黑激素（MLT）在兔血清中的高效液相色谱测定方法，研究MLT在兔体内的药动学。方法 采用YWG-C₁₈色谱柱4.6 mm×150 mm；以乙腈 磷酸缓冲液（41∶59）为流动相，维拉帕米作内标，流速为1 mL·min^-1，荧光检测，激发波长280 nm，发射波长340 nm。结果 MLT在0.5～64 μg·L^-1范围内具有良好的线性关系，最低检测浓度为0.25 μg·L^-1，平均萃取回收率为（82.55±5.33）%，平均方法回收率为（100.12±0.98）%，日内RSD＜5%，日间RSD＜5%，家兔耳缘静脉注射MLT 0.25 mg·kg^-1，t_1/2β为(1.55±0.21) h，AUC_0～8为（27.73±1.03）μg·h·L^-1。结论 本法具有快速、简便、灵敏准确的特点，用于MLT生物样本分析，结果良好

HPLC determination of melatonin and study on its pharmacokinetics in ra bbits

OBJECTIVE A HPLC method was described for the analysis of melatonin (MLT) in serum and to study the pharmacokinetics of MLT in rabbits.METHODS The YWG-C₁₈ column (150 mm×4.6 mm,5 μm) was used.The mobile phase was consisted of a mixture of acetonitrile-phosphate (pH 3.0).The flow rate was 1 mL·min^-1.Fluorescence detector was used with Ex at 280 nm and Em at 340 nm.Verapamil was used as the internal standard.RESULTS A good linearity was obtained from 0.5～64 μg·L^-1 of MLT in rabbit serum with r=0.9990.The lowest detectable concentration was 0.25 μg·L^-1.While the average recovery of the method was (100.12 ±0.98)%,the RSD of intra-day and inter-day variation was less than 5%.The main pharmacokinetic parameters after iv administration of MLT in rabbits were t_1/2β (1.55±0.21) h and AUC_0～∞(27.73±1.03) μg·h·L^-1,respectively.CONCLUSION The established HPLC method was simple and accurate for the determination of MLT in serum.