Search

A rapid, sensitive and reliable liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of betulonic acid in rat plasma. The plasma samples were prepared by protein precipitation. Chromatographic separation was achieved on an Agela MG-C18 analytical column (50 × 2.1 mm, 5 µm) using methanol–water–formic acid (80:20:0.1, v/v/v) as the mobile phase with a constant flow rate of 0.6 mL/min. Mass detection was conducted by electrospray ionization in positive ion multiple reaction monitoring mode. The calibration curves were linear over a concentration range of 3.00–3,000 ng/mL for the analyte. The intra-day and inter-day accuracy and precision were within the acceptable limits of ±15% at all concentrations. The method was successfully applied for the estimation of betulonic acid in rat plasma from a preclinical pharmacokinetics study. [ABSTRACT FROM AUTHOR]

Abstract: A sensitive method for the quantification of oxaceprol in rat plasma using high-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed. Sample pretreatment involved a simple protein precipitation by the addition of 60μL of acetonitrile–methanol (1:2, v/v) to 20μL plasma sample volume. Separation was achieved on a Dikma ODS-C18 (5μm, 150mm×4.6mm) reversed-phase column at 40°C with acetonitrile/0.1% formic acid–4mM ammonium acetate in water (35:65,v/v) at a flow rate of 0.6mL/min. Detection was performed using an electrospray ionization (ESI) operating in negative ion multiple reaction monitoring (MRM) mode by monitoring the ion transitions from m/z 172→130 (oxaceprol) and m/z 153→109 (protocatechuic acid, internal standard). The calibration curve of oxaceprol in plasma showed good linearity over the concentration range of 1.25–800ng/mL. The limit of detection and limit of quantification were 0.400ng/mL and 1.25ng/mL, respectively. Intra- and inter-day precisions in all samples were within 15%. There was no matrix effect. The validated method was successfully applied to a preclinical pharmacokinetic study of oxaceprol in rats. After oral administration of 20mg/kg oxaceprol to rats, the main pharmacokinetic parameters T max, C max, T 1/2, V z/F and AUC0–t were 1.4h, 1.2μg/mL, 2.3h, 19.7L/kg and 3.4mgh/L, respectively. [ABSTRACT FROM AUTHOR]