A sensitive and highly selective liquid chromatography-mass spectrometry (LC-MS) method
was developed to determine nitrendipine (4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,
5-pyridinedicarboxylic acid ethyl methyl ester, CAS 39562-70-4) in human plasma. The
analyte and the internal standard nimodipine (CAS 66085-59-4) were extracted from
plasma samples by n-hexane-isopropanol (95:5, v/v), and analyzed on a commercially
available column interfaced with a mass spectrometer. Positive atmospheric pressure
chemical ionization (APCI) was empolyed as the ionization source. The samples were
detected by the use of selected ion monitoring (SIM) mode. The mobile phase consisted
of methanol-water (75:25, v/v). The method has a limit of detection (LOD) of 0.1 ng/ml.
The linear calibration curves were obtained in the concentrations range of 0.3–40
ng/ml (r2≥0.99). The intra- and inter-day batch precisions were lower than 10% in terms of
relative standard deviation (R. S. D.), and the accuracy ranged from 85 to 110% in
terms of percent accuracy. The overall extraction recoveries were determined to be
about 75% on average. This validated method was successfully applied to the evaluation
of the pharmacokinetic profiles of nitrendipine tablets administered to 8 Chinese
healthy volunteers.
Key words
Calcium antagonists, 1,4-dihydropyridine - CAS 39562-70-4 - Nitrendipine, bioavailability,
LC-MS method, pharmacokinetics
