大鼠血浆中厄他培南的HPLC法测定及初步药动学研究

目的：建立一种快捷、灵敏的高效液相色谱法测定大鼠血浆中的厄他培南，并考察其在大鼠体内的药动学。方法：以甲硝唑为内标，血浆样品经过甲醇沉淀蛋白，离心，取上清液进行HPLC分析。使用Diamonsil C₁₈（4.6 mm×150 mm，5.0 μm）色谱柱，流动相为乙腈-10 mmol·L^-1醋酸钠溶液（11.4：88.6），流速1.0 mL·min^-1，检测波长295 nm，柱温35℃，进样量10 μL。结果：血浆中厄他培南浓度在2~200 μg·mL^-1范围内线性关系良好（r=0.999 8）；厄他培南的绝对回收率为（96.4±1.7）%~（99.3±1.2）%，方法回收率为（87.6±3.1）%~（107.9±2.5）%；内标甲硝唑的绝对回收率为（98.1±1.9）%；日内、日间精密度均小于5%；中浓度的血浆样品在常温放置3 h、-40℃保存7 d及反复冻融3次，均能保持稳定；稀释效应精密度为0.4%。大鼠静脉注射厄他培南100 mg·kg^-1后的主要药动学参数分别为AUC_0→t（207.9±19.7）μg·h·mL^-1，AUC_0→∞（209.1±20.4）μg·h·mL^-1，t_1/2（0.4±0.05）h，CL（0.48±0.05）L·（h·kg）-1，V（0.29±0.02）L·kg^-1。结论：此HPLC法测定大鼠体内厄他培南浓度，方法准确快捷，灵敏度高，重复性好，适合该药的药动学研究。

Objective: To establish a rapid, sensitive method for the determination of ertapenem in rat plasma, and its preliminary pharmacokinetics in rats was also investigated.Methods: Taking metronidazole as an internal standard, the plasma samples were extracted by methanol to precipitate protein.After centrifugation, the supernatant was analyzed by HPLC.A Diamonsil C₁₈(4.6 mm×150 mm, 5.0 μm) column was used, with the mobile phase of acetonitrile-10 mmol·L^-1 sodium acetate solution(11.4:88.6), flow rate of 1 mL·min^-1, detection wavelength of 295 nm, column temperature of 35℃, sample volume of 10 μL.Results: The method was validated over the concentration range of 2-200 μg·mL^-1 for ertapenem in rat plasma, and there was excellent linearity(r=0.999 8). The extraction recoveries for ertapenem were(96.4±1.7)%-(99.3±1.2)%, while its method recoveries were(87.6±3.1)%-(107.9±2.5)%.The extraction recovery for the internal standard metronidazole was(98.1±1.9)%;the intra-day and inter-day RSDs were both below 5%;All the analytes of medium concentrations in serum were stable at room temperature for 3 h at -40℃ for 7 days and after three-cycle freeze-thaw;Effect of dilution RSD was 0.4%.The major pharmacokinetic parameters after iv administration of ertapenem 100 mg·kg^-1 to rats were as follows:AUC_0→t(207.9±19.7)μg·h·mL^-1, AUC_0→∞(209.1±20.4)μg·h·mL^-1, t_1/2(0.4±0.05) h, CL(0.48±0.05) L·(h·kg)-1, V(0.29±0.02) L·kg^-1.Conclusion: HPLC method for the determination of ertapenem concentration in plasma is rapid, simple, accurate and sensitive, which is also suitable for pharmacokinetic study.