柱切换HPLC测定血浆中消旋卡多曲的活性代谢物thiophine

Determination of the active metabolite of racecadotril-thiophine in human plasma by column-switching RP-HPLC method

目的 建立柱切换RP—HPLC测定消旋卡多曲的活性代谢物（thiophine，TP）浓度的方法。方法 采用Kromasil C18预柱（25mm×4．6mm，5μm）和分析柱（100mm×4．6mm,5μm），流动相均为0．02mol·L^-1磷酸二氢钾-乙腈（80：20）；取已加抗氧剂的血浆0．5ml，加入pH2．0的磷酸盐缓冲液酸化，经C18 SPE柱萃取后进样，在210nm处检测，按外标法定量。结果标准曲线在25．0～3．2×10^3g·L^-1范围内有良好的线性，最低定量限为25μg·L^-1，TP的保留时间为4．7min，日内RSD〈8％，日间RSD〈9．5％，方法回收率95％-115％。结论 所建方法快速简便，灵敏准确，适用于TP血药浓度的测定及卡多曲的药物动力学、生物利用度的研究。

OBJECTIVE To establish a column - switching RP - HPLC method with UV detection for the determination of thiophine （TP） , an active metabolite of racecadotril, in human plasma. METHODS A variable wavelength UV detector, Kromasil Cls pretreatment column （25 mm×4.6 mm, 5μm） and analytical column （100 mm ×4.6 mm, 5μm） were used. The acidified plasma sample was extracted with C18 SPE cartridge columns. The mobile phase of 0.02 mol·L^-1 phosphate- acetonitrile （80 ： 20） was pumped at 1.0 ml· min^-1 through the both pretreatment and analytical column, with the column - switching time from 0.58 min to 1.70 min. The detector at 0.06 AUFS was set at 210 nm. RESULTS The retention time for TP was 4.7 min. The standard curve was linear over the concentration range of 25.0μg·L^-1 to 3.2 ×10^3 μg·L^-1, and the lowest concentration of detection in plasma was 25 μg·L^-1. The method recovery was 95% to 115% with intra day RSD less than 8% and of inter day RSD less than 9.5%. CONCLUSION This method is suitable for determination of TP in human plasma,