Piperazine scaffold: A remarkable tool in generation of diverse pharmacological agents.

Therapeutic drug monitoring and LC–MS/MS

A study of Semen Strychni-induced renal injury and herb-herb interaction of Radix Glycyrrhizae extract and/or Rhizoma Ligustici extract on the comparative toxicokinetics of strychnine and brucine in rats.

Recent developments in the field of the determination of constituents of TCMs in body fluids of animals and human.

A rapid, highly sensitive, and selective method was developed for the determination of the insecticide chlorantraniliprole (CAP) in corn and soil using ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). Samples were extracted with acetonitrile, and aliquots were cleaned with solid-phase extraction cartridges. Two precursor-product ion transitions for CAP were measured and evaluated to provide maximum confidence in the results. Average recovery for soil, corn grain, and corn straw at different levels (5 or 10, 40, and 100 μg kg−1) ranged from 74.9 to 97.5%, with intra-day relative standard deviation (RSD) values of 1.9–11.3% and inter-day RSD values of 4.7–10.4%. Coefficients of determination (R 2) of 0.9988 or higher were achieved for CAP in soil, corn grain, and corn straw matrix calibration curves, from 5 to 1,000 μg L−1. The CAP limits of quantitation in soil, corn grain, and straw were determined to be 5, 10, and 10 μg kg−1, respectively, which were much lower than the maximum residue levels established by the Environmental Protection Agency of United States. UPLC–MS/MS was used to determine the CAP residues in real corn and soil for studies on their dissipation. The trial results showed that the half-lives of CAP changed from 12.6 to 23.1 days in soils and ranged from 4.9 to 5.4 days in corn straws in the districts of Henan and Shandong, and the average levels of CAP residues in corn grains were all <0.01 mg kg−1 with a harvest withholding period of 180 days.

Determination of Chlorantraniliprole Residues in Corn and Soil by UPLC–ESI–MS/MS and Its Application to a Pharmacokinetic Study

Ultra-performance liquid chromatography–tandem mass spectrometric method for the determination of strychnine and brucine in mice plasma

Quantification of prochlorperazine maleate in human plasma by liquid chromatography-mass spectrometry: Application to a bioequivalence study.

A simple, rapid, and selective method to determine the concentration of ziprasidone hydrochloride in schizophrenics’ plasma using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) was developed and validated. The UPLC separation was carried out with an Acquity UPLC BEH C18 column (50 × 2.1 mm i.d., 1.7 μm particle size). The mobile phase consisted of methanol–water (50:50, v/v; the water included 15 mM NH4Ac and 0.125% acetic acid). The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) at m/z 412.82 → 193.75 for ziprasidone and m/z 236.87 → 193.76 for the internal standard, carbamazepine. Solid-phase extraction was used to extract ziprasidone hydrochloride and carbamazepine from plasma. Ziprasidone and the internal standard eluted as sharp, symmetrical peaks with retention times of 1.24 ± 0.01 min and 1.74 ± 0.02 min, respectively. Calibration curves of ziprasidone at concentrations ranging from 0.7 to 400 ng mL−1 exhibited excellent linearity (r = 0.9995), with a lower limit of quantification of 0.7 ng mL−1. Intra- and inter-day relative standard deviations were less than 7.75% RSD and 5.43% RSD, respectively. The extraction recovery was above 81.3%. The described assay method showed acceptable precision, accuracy, linearity, stability, and specificity and can be used for pharmacokinetic studies.

Determination of Ziprasidone by UPLC-MS-MS and Its Application to a Pharmacokinetic Study of Chinese Schizophrenics

A simple, rapid, and selective method to determine the concentration of ziprasidone hydrochloride in schizophrenics' plasma using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) was developed and validated. The UPLC separation was carried out with an Acquity UPLC BEH C18 column (50 × 2.1 mm i.d., 1.7 µm particle size). The mobile phase consisted of methanol-water (50:50, v/v; the water included 15 mM NH4Ac and 0.125% acetic acid). The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) at m/z 412.82 → 193.75 for ziprasidone and m/z 236.87 → 193.76 for the internal standard, carbamazepine. Solid-phase extraction was used to extract ziprasidone hydrochloride and carbamazepine from plasma. Ziprasidone and the internal standard eluted as sharp, symmetrical peaks with retention times of 1.24 ± 0.01 min and 1.74 ± 0.02 min, respectively. Calibration curves of ziprasidone at concentrations ranging from 0.7 to 400 ng mL–1 exhibited excellent linearity (r = 0.9995), with a lower limit of quantification of 0.7 ng mL–1. Intra- and inter-day relative standard deviations were less than 7.75% RSD and 5.43% RSD, respectively. The extraction recovery was above 81.3%. The described assay method showed acceptable precision, accuracy, linearity, stability, and specificity and can be used for pharmacokinetic studies.

Yan-Qing Lei

Papers

Ultra-performance liquid chromatography–tandem mass spectrometric method for the determination of strychnine and brucine in mice plasma

Ultra-performance liquid chromatography–tandem mass spectrometric method for the determination of strychnine and brucine in mice plasma

Quantification of prochlorperazine maleate in human plasma by liquid chromatography-mass spectrometry: Application to a bioequivalence study.

Determination of Ziprasidone by UPLC-MS-MS and Its Application to a Pharmacokinetic Study of Chinese Schizophrenics

Determination of ziprasidone by UPLC-MS-MS and its application to a pharmacokinetic study of Chinese schizophrenics.