UHPLC-MS/MS法测定比格犬血浆中硝苯地平的浓度

目的：建立UHPLC-MS/MS法测定硝苯地平缓释片在比格犬血浆中的药物浓度。方法：血浆经乙醚-正己烷（2：1）提取，以地西泮为内标，采用UHPLC-MS/MS方法测定6只比格犬口服硝苯地平缓释片20 mg后血浆中的药物浓度。UHPLC条件:采用Shim-pack XR-ODS色谱柱（75 mm×3.0 mm，2.2 μm），以甲醇（B）-0.05%甲酸水（A）为流动相，洗脱梯度（0～2.00 min，80%B→95%B；2.01～2.20 min，95%B；2.21～3.50 min，80%B），流速0.4 mL·min^-1，柱温40℃，分析时间总计3.50 min，进样量5 μL;条件：硝苯地平：m/z347.0→m/z315.0，DP为58 V，CE为10 V，CXP为21 V；地西泮（内标）：m/z285.0→m/z193.1，DP为80 V，CE为43 V，CXP为20 V。结果：硝苯地平在浓度为0.15～50.00 ng·mL^-1范围内线性关系良好（r=0.9983），日内精密度RSD（n=6）≤6.6%，日间精密度RSD（n=6）≤13.8%，绝对回收率（n=6）为63.1%～68.3%，基质效应（n=6）RSD≤7.5%。6只比格犬口服硝苯地平缓释片20 mg后的主要药动学参数T_max为（4.58±1.39）h，C_max为（30.53±7.38）ng·mL^-1，t_1/2为（8.69±3.42）h，AUC_0-t为（185.9±113.3）ng·h·mL^-1，AUC_0-∞为（188.8±113.6）ng·h·mL^-1。结论：本方法简单、快速、灵敏，重现性好，可用于测定硝苯地平缓释片的血药浓度并进行药动学评价。

Objective: To develop a UHPLC-MS/MS method for the determination of the drug concentration in Beagles plasma after oral administration of nifedipine sustained-release tablets. Methods: Diazepam was used as the internal standard.The concentration of nifedipine in the six Beagles plasma was determined by UHPLC-MS/MS after oral administration of 20 mg of nifedipine sustained-release tablets.Nifedipine and internal standard were separated by Shim-pack XR-ODS(75 mm×3.0 mm,2.2 μm)and extracted from plasma by ethyl ether-n-hexane(2: 1).Mobile phase was methanol-0.05% formic acid in water with gradient elution(0-2.00 min,80%B→95%B;2.01-2.20 min,95%B;2.21-3.50 min,80%B),the flow rate was 0.4 mL·min^-1 with the column temperature of 40℃,the total analysis time was 3.50 min and the inject volume was 5 μL;MS:nifedipine:m/z 347.0→m/z 315.0,DP:58 V,CE:10 V,CXP:21 V;diazepam(internal standard):m/z 285.0→m/z 193.1,DP:80 V,CE:43 V,CXP:20 V.Results: The linear range of nifedipine in the plasma was 0.15-50.00 ng·mL^-1(r=0.9983),the intra-day and inter-day precisions were lower than 6.6%(n=6)and 13.8%(n=6),the recovery(n=6)was 63.1%-68.3% and the RSD(n=6)of matrix effect was lower than 7.5%.The main pharmacokinetic parameters of nifedipine in Beagles were as follows:T_max was(4.58±1.39)h,C_max was(30.53±7.38)ng·mL^-1,t_1/2 was(8.69±3.42)h,AUC_0-t was(185.9±113.3)ng·h·mL^-1,and AUC_0-∞ was(188.8±113.6)ng·h·mL^-1. Conclusion: The method is simple,fast,sensitive and reproducible for the determination of nifedipine in nifedipine sustained-release tablets and in the pharmacokinetic assays.