Streel B, Zimmer C, Sibenaler R, Ceccato A
S.M.B. Laboratories R&D (Galephar), Brussels, Belgium.
J Chromatogr B Biomed Sci Appl. 1998 Dec 11;720(1-2):119-28. doi: 10.1016/s0378-4347(98)00423-x.
Quantitative analysis of therapeutic compounds and their metabolites in biological matrix (such as plasma, serum or urine) nowadays requires sensitive and selective methods to allow the determination of concentrations in the ng/ml range. A new on-line LC-MS-MS method using atmospheric pressure chemical ionisation (APCI) as interface for the simultaneous determination of nifedipine (NIF) and its metabolite in human plasma, dehydronifedipine (DNIF) has been developed. The compounds were extracted from plasma using solid-phase extraction (SPE) on disposable extraction cartridges (DECs). The SPE operations were performed automatically by means of a sample processor equipped with a robotic arm (ASPEC system). The DEC filled with phenyl modified silica was first conditioned with methanol and water. The washing step was performed with water. Finally, the analytes were successively eluted with methanol and water. The liquid chromatographic (LC) separation of NIF and DNIF was achieved on a RP-18 stationary phase (4 microm). The mobile phase consisted of methanol-50 mM ammonium acetate solution (50:50, v/v). The LC was then coupled to tandem mass spectrometry with an APCI interface in the positive ion mode. The method developed was validated. The absolute recoveries evaluated over the whole concentration range were 95+/-2% and 95+/-4% for NIF and DNIF, respectively. The method was found to be linear in the 0.5-100 ng/ml concentration range for the two analytes (r2 = 0.999 for both NIF and DNIF). The mean R.S.D. values for repeatability and intermediate precision were 2.9 and 3.0% for NIF and 2.2-4.7% for the metabolite. The method developed was successfully used to investigate the plasma concentration of NIF and DNIF in the pharmacokinetic studies.
如今，对生物基质（如血浆、血清或尿液）中的治疗性化合物及其代谢物进行定量分析需要灵敏且具选择性的方法，以便测定纳克/毫升范围内的浓度。已开发出一种新的在线液相色谱 - 串联质谱法，该方法使用大气压化学电离（APCI）作为接口，用于同时测定人血浆中的硝苯地平（NIF）及其代谢物脱氢硝苯地平（DNIF）。使用一次性萃取小柱（DEC）上的固相萃取（SPE）从血浆中提取化合物。SPE操作通过配备机器人手臂的样品处理器（ASPEC系统）自动进行。填充有苯基改性硅胶的DEC先用甲醇和水进行预处理。用水进行洗涤步骤。最后，分析物依次用甲醇和水洗脱。NIF和DNIF的液相色谱（LC）分离在RP - 18固定相（4微米）上实现。流动相由甲醇 - 50 mM醋酸铵溶液（50:50，v/v）组成。然后将LC与具有正离子模式的APCI接口的串联质谱联用。所开发的方法经过了验证。在整个浓度范围内评估的NIF和DNIF的绝对回收率分别为95±2%和95±4%。发现该方法在两种分析物的0.5 - 100 ng/ml浓度范围内呈线性（NIF和DNIF的r2均为0.999）。NIF的重复性和中间精密度的平均相对标准偏差值分别为2.9%和3.0%，代谢物的为2.2 - 4.7%。所开发的方法成功用于药代动力学研究中NIF和DNIF的血浆浓度研究。
