目的 通過LC-MS/MS法測(cè)定大鼠血漿中依那普利活性代謝產(chǎn)物依那普利拉濃度,研究依那普利在大鼠體內(nèi)的藥動(dòng)學(xué)。方法 Wistar大鼠ig依那普利15 mg/kg,采用固相萃取法對(duì)大鼠血漿樣品預(yù)處理,洗脫液為甲醇、水。色譜與質(zhì)譜條件為Diamond C₁₈色譜柱(150 mm×4.6 mm,5 μm);流動(dòng)相:乙腈–5 mmol/L乙酸銨(45:55);體積流量:0.5 mL/min;柱溫:30 ℃;進(jìn)樣量:5 μL。采用ESI(＋)離子源;干燥氣(N₂)體積流量11.0 L/min,壓力275.8 kPa,溫度350 ℃;毛細(xì)管電壓3 500 V;多級(jí)反應(yīng)監(jiān)測(cè)(MRM)模式,正離子模式;EMV為400 eV。結(jié)果 血漿中內(nèi)源性物質(zhì)對(duì)測(cè)定無干擾,依那普利拉的線性范圍為20~1 500 ng/mL,最低定量限為20 ng/mL。準(zhǔn)確度和精密度良好。血漿樣本中依那普利拉的提取回收率大于85%,且無濃度相關(guān)性。經(jīng)2次凍融以及冷凍14 d穩(wěn)定良好。大鼠體內(nèi)依那普利拉的主要藥動(dòng)學(xué)參數(shù):AUC₀-_t為(8015±297.7)ng/mL·h,C_max為(1 405±269.10)ng/mL,t_max為(2.45±0.19)h,t_1/2為(4.82±0.32)h,Clz/F為(2.18±0.10)L/kg·h,Vz/F為(12.63±1.31)L/kg。結(jié)論 本方法專屬性強(qiáng)、靈敏度高、準(zhǔn)確性好。通過測(cè)定代謝產(chǎn)物依那普利拉經(jīng)時(shí)血藥濃度,可以考察依那普利的藥動(dòng)學(xué)特征。

Objective To investigate the pharmacokinetics of enalapril in rat by establishing LC-MS/MS method for determination of enalaprilat, active metabolite of enalapril in rat plasma. Methods Wistar rats were ig administered with a single dose 15 mg/kg of enalapril. Plasma samples were pretreated by solid-phase extraction, and elution solutions were methanol and water. The separation was performed on Diamonsil C₁₈ column (150 mm × 4.6mm, 5 μm) with mobile phase consisted of acetonitrile-5mmol/L ammonium (45:55) at 0.5 mL/min. The column temperature was set at 30 ℃, and the flow rate was 0.5 mL/min with injection volume of 5 μL. Enalaprilat was determined by LC-MS/MS in the positive ion multiple reaction monitoring (MRM) mode with EMV 400 eV. ESI (+) ion source was used, dry gas (N₂) had flow rate of 11.0 L/min, pressure was 275.8 kPa with temperature 350 ℃, and capillary voltage was 3 500 V. Results No endogenous interfering peak was observed in chromatograms. The calibration curve was linear over the concentration range of 20 - 1 500 ng/mL, and the lower limit of quantitation was 20 ng/mL. Accuracy and precision met the requirements. The recovery of enalaprilat was more than 85% with no concentration dependence. The plasma samples were stable after two freeze-thaw cycles and after being stored for 14 d. Main pharmacokinetic parameters of enalaprilat were as following: AUC_0-t (8 015 ± 297.7) ng/mL·h, C_max (1 405 ± 269.10) ng/mL, t_max (2.45 ± 0.19)h, t_1/2 (4.82 ± 0.32) h, Clz/F (2.18 ± 0.10) L/kg·h, Vz/F (12.63 ± 1.31) L/kg. Conclusions The method is excellent specificity, acceptable precision, and accuracy. The pharmacokinetics of enalaprilat, the active metabolite of enalapril in plasma could be investigated by determine the concentration-time, and pharmacokinetic characteristics of enalapril drug can also be investigated.