A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method using positive/negative electrospray ionization (ESI) switching for the simultaneous quantitation of p-acetaminobenzoic acid (PABA) and N, N-dimethylamino-2-propanol (DIP) in human plasma has been developed and validated. After simple protein precipitation using acetonitrile, the analytes and internal standard (IS) diazepam were separated on a CAPCELL PAK Phenyl column (150 x 2.0 mm, 5 mu m) using formic acid : water (1:1000, v/v) as solvent A and acetonitrile as solvent B at a flow rate of 0.4 mL min(-1). N,N-Dimethylamino-2-propanol and the IS were detected by positive ion electrospray ionization followed by multiple reaction monitoring (MRM) of the transition at m/z 104.0 -> 86.1 and 256.3 -> 167.1, respectively. p-Acetaminobenzoic acid was detected by negative ion electrospray ionization followed by MRM of the transitions at m/z 178.1 -> 134.0. The method was linear for PABA and DIP in the concentration range of 0.02-10 mu g mL(-1) with intra-and inter-day precisions (as relative standard deviation) of <= 5.81% and accuracy (as relative error) of <= 6.52% and the limit of detection (LOD) values were 10 and 5 ng mL(-1), respectively. The method was successfully applied to a pharmacokinetic study of the analytes in humans after oral administration of 1.0 g inosiplex tablets.
[1]Jilin Univ, Hosp 1, Dongminzhu St, Changchun 130061, Peoples R China.
[2]Jilin Univ, Sch Life Sci, Qianjin St, Changchun 130012, Peoples R China.
[3]Jilin Univ, Res Ctr Drug Metab, Qianjin St, Changchun 130012, Peoples R China.
[4]Chinese Med Univ, Clin Hosp 2, Shenyang 110004, Peoples R China.
(8.0+极速模式)