Determination of tropisetron in human plasma by liquid chromatography–tandem mass spectrometry

Quantification of ondansetron, granisetron and tropisetron in goat plasma using hydrophilic interaction liquid chromatography-solid phase extraction coupled with hydrophilic interaction liquid chromatography-triple quadrupole tandem mass spectrometry

An assay method to quantify ondansetron (OND), granisetron (GRA) and tropisetron (TRO) in goat plasma has been successfully developed and validated. This method procedure for the analysis of OND, GRA and TRO was involved of extracting samples with hydrophilic interaction liquid chromatography (HILIC) solid phase extraction (SPE) and determination by liquid chromatography coupled to tandem mass spectroscopy. An SPE method for the simultaneous extraction of OND, GRA and TRO with high efficiency and selectivity was developed. Prior to HPLC-MS/MS analysis, most of the sources of interference present in the supernatant after protein precipitation of plasma proteins was efficiently removed from the samples by the HILIC SPE treatment. For the quantification of OND, GRA and TRO in the samples, tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring was used. The calibration curve was performed in the range of 0.2-20 ng/mL for the target OND, GRA and TRO in goat plasma samples. The precision of the intra- and inter-day assay for OND, GRA and TRO were 1.84-6.23% and 3.89-5.31%, 2.63-6.29% and 3.76-5.31%, 1.99-5.67% and 2.64-4.70%, respectively. The accuracy of the intra- and inter-day assay for OND, GRA and TRO were 89.15-97.39% and 89.46-95.17%, 91.08-100.82% and 91.24-99.47%, 92.30-100.74% and 94.21-97.90%, respectively. For the determination of OND, GRA and TRO in plasma samples, no significant matrix effects were observed. The mean absolute recoveries were 103-150%, 115-121%, and 98-141% for OND, GRA and TRO, respectively. Furthermore, the mean process efficiency values of silica SPE were 98-135%, 92-124%, and 72-109% for OND, GRA and TRO, respectively.

Study on the interactions of antiemetic drugs and 12-tungstophosphoric acid by absorption and resonance Rayleigh scattering spectra and their analytical applications

In 0.1 mol L(-1) HCl medium, antiemetic drugs (ATM), such as granisetron hydrochloride (GS) and tropisetron hydrochloride (TS), reacted with H(3)PW(12)O(40)·nH(2)O and formed 3:1 ion-association complex of [(ATM)(3)PW(12)O(40)], then self-aggregated into nanoparticles-[(ATM)(3)PW(12)O(40)](n) with an average size of 100 nm. The reaction resulted in the enhancement of resonance Rayleigh scattering (RRS) and the absorption spectra. The increments of scattering intensity (ΔI(RRS)) and the change of absorbance (ΔA) were both directly proportional to the concentrations of ATM in certain ranges. Accordingly, two new RRS and spectrophotometric methods were proposed for ATM detection. The detection limits (3σ) of GS and TS were 3.2 ng mL(-1) and 4.0 ng mL(-1)(RRS method), 112.5 ng mL(-1) and 100.0 ng mL(-1)(spectrophotometric method). These two methods were applied to determine GS in orally disintegrating tablets and the results were in good agreement with the official method. The ground-state geometries and electronic structures of GS and TS were optimized by the hybrid density functional theory (DFT) method and the shape of [(ATM)(3)PW(12)O(40)](n) was characterized by atomic force microscopy (AFM). Take the RRS method with higher sensitivity as an example, the reaction mechanism and the reasons for enhancement of scattering were discussed.

Determination of azasetron hydrochloride in rabbit plasma by liquid chromatography tandem mass spectrometry and its application

A sensitive and selective liquid chromatography tandem mass spectrometry method for determination of azasetron hydrochloride in rabbit plasma was developed. After addition of doxapram hydrochloride as internal standard (IS), protein precipitation by 10% trichloroacetic acid was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB-C(18) (2.1 × 50 mm, 3.5 µm) column with acetonitrile-water as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring mode was used to quantification using target fragment ions m/z 349.9 → 223.5 for azasetron hydrochloride and m/z 378.9 → 291.8 for the IS. Calibration plots were linear over the range of 6-1000 ng/mL for azasetron hydrochloride in plasma. The lower limit of quantitation for azasetron hydrochloride was 6 ng/mL. The mean recovery of azasetron hydrochloride from plasma was in the range 85.6-92.7%. The RSDs of intra-day and inter-day precision were both less than 12%. This method is simple and sensitive enough to be used in pharmacokinetic research for determination of azasetron hydrochloride in rabbit plasma.