A selective, sensitive, high pressure liquid chromatography-positive electrospray ionization tandem mass spectrometry method was developed and validated for the quantification of aripiprazole in human K(2)EDTA plasma using zolpidem tartrate as an internal standard. The analyte and internal standard were extracted from human plasma by solid-phase extraction using methanol. The eluted samples were chromatographed on a Grace Smart RP 18 4.6 × 100 mm, 3 µ column by using a 95:5 v/v mixture of methanol and ammonium acetate buffer (30 mM, pH 5.0 ± 0.05) as a gradient mobile phase at a flow rate of 0.6 mL/min, and analyzed by mass spectrometry in the multiple reaction monitoring mode using the [M + H](+) ions m/z 448.03 → 285.14 for aripiprazole and m/z 308.13 → 235.25 for the internal standard (zolpidem tartrate), respectively. Calibration plots were linear over the concentration range of 0.20 to 60.01 ng/mL. Intra-day and inter-day precision (percent coefficient of variation) and accuracy (percent nominal) for quality control samples (0.60, 30.60 and 45.59 ng/mL) ranged between 2.28 and 8.93% and between 92.50 and 107.07%, respectively. Extraction recovery of aripiprazole from plasma was in the range 75.56-79.57%; mean recovery was 77.35%. The main pharmacokinetic parameters were T(max) = (4.00 ± 2.336) C(max) = (55.16 ± 13.490) and AUC = (1846.28 ± 484.686).

A rapid and high sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the quantification of zolpidem in human EDTA plasma using ondansetron (IS) as an internal standard. The analyte and IS were extracted from human plasma using ethyl acetate and separated on a C18 column (Inertsil-ODS, 5 µm, 4.6 × 50 mm) interfaced with a triple quadrupole tandem mass spectrometer. The mobile phase, which consisted of a mixture of methanol and 20 mM ammonium formate (pH 5.00 ± 0.05; 75:25 v/v), was injected at a flow rate of 0.40 mL/min. The retention times of zolpidem and IS were approximately 1.76 and 1.22. The LC run time was 3 min. The electrospray ionization source was operated in positive ion mode. Multiple reaction monitoring used the [M + H](+) ions m/z 308.13 → 235.21 for zolpidem and m/z 294.02 → 170.09 for the ondansetron, respectively. Five freeze-thaw cycles was established at -20 and -70°C.The linearity of the response/concentration curve was established in human EDTA plasma over the concentration range 0.10-149.83 ng/mL. The lower detection limit [(signal-to-noise (S/N) > 3] was 0.04 ng/mL and the lower limit of quantification (S/N > 10) was 0.10 ng/mL. This LC-MS-MS method was validated with intra-batch and inter-batch precision of 0.52-8.66.The intra-batch and inter-batch accuracy was 96.66-106.11. Recovery of zolpidem in human plasma was 87.00% and IS recovery was 81.60%. The primary pharmacokinetic parameters were T(max) (h) = (1.25 ± 0.725), C(max) (ng/mL) (127.80 ± 34.081), AUC(0→t), = (665.37 ± 320.982) and AUC(0→∞), 686.03 ± 342.952, respectively.

Objective: To propose a comprehensive, simple, and affordable RP-HPLC method for impurity profiling and characterization of unknown degradation products of thiamine hydrochloride injectable formulation. Methods: The chromatographic separation employs gradient mode using the octadecyl silane column using a mobile phase consisting of phosphate buffer with ion pair reagent, acetonitrile, and methanol delivered flow rate at 1.2 ml/min. The detection was carried out at 248 nm using empower software. LC-MS/MS/QTOF hyphenated technique was used for isolation and characterization of unknown degradation impurity. The performance of the method was systematically validated as per ICH Q2 (R1) guidelines. Results: Degradation product observed in accelerated stability was characterized by LC-MS/MS/QTOF hyphenated technique and found m/z value 351.1604 and postulated as an oxidative degradation product of thiamine due to excipient interaction. The validated method was sensitive, selective, and specific data proves the method is precise and accurate from LOQ to 150% level and results are within 95-108% and less than 4.5% RSD. The developed method is linear from 0.03-58.83 µg/ml with a correlation coefficient of more than 0.990 and LOD and LOQ value ranged from 0.03 to1.51 μg/ml. Conclusion: An efficient RP-HPLC method for impurity profiling of thiamine injectable formulation was successfully developed and unknown degradation product observed instability condition samples characterized by LC-MS/MS/QTOF technique. The validated method can be successfully employed for the impurity profiling of thiamine injectable in the quality control department.