Development and validation of a liquid chromatographic/electrospray ionization mass spectrometric method for the quantitation of prazepam and its main metabolites in human plasma

Abstract

A method was developed and fully validated for the quantitation of prazepam and its major metabolites, oxazepam and nordiazepam, in human plasma. Sample pretreatment was achieved by solid-phase extraction using Oasis HLB cartridges. The extracts were analysed by high-performance liquid chromatography (HPLC) coupled with single-quadrupole mass spectrometry (MS) with an electrospray ionization interface. The MS system was operated in the selected ion monitoring mode. HPLC was performed isocratically on a reversed-phase XTerra MS C18 analytical column (150 x 3.0 mm i.d., particle size 5 microm). Diazepam was used as the internal standard for quantitation. The assay was linear over a concentration range of 5.0-1000 ng ml(-1) for all compounds analyzed. The limit of quantitation was 5 ng ml(-1) for all compounds. Quality control samples (5, 10, 300 and 1000 ng ml(-1)) in five replicates from three different runs of analysis demonstrated an intra-assay precision (CV) of < or = 9.1%, an inter-assay precision of < or = 6.0% and an overall accuracy (relative error) of < 4.6%. The method can be used to quantify prazepam and its metabolites in human plasma covering a variety of pharmacokinetic or bioequivalence studies.

Validated method for determination of bromopride in human plasma by liquid chromatography–electrospray tandem mass spectrometry: application to the bioequivalence study

“…Bromopride is chemically related to metoclopramide and is administered as a single oral dose over a range of 10 to 30 mg. Bromopride has a volume of distribution (a measure of the apparent space in the body available to contain the drug) 1 of 3.07 l/kg, and it is only bound 40% to plasma protein 2,3 and reaches a dose-related maximum peak concentration (C max D 20 to 64 ng/ml) in 2.8 h. The systemic bioavailability (related to the concentration of the drug in the plasma) ranges from 54 to 78% and its elimination half-life is around 4.9 h. Quantification of drugs in biological matrices by liquid chromatography-tandem mass spectrometry (LC-MS/MS) is becoming more common, because of the improved sensitivity and specificity of this technique. 4,5,6 Some other techniques have been used to determine bromopride in a variety of matrices. Such methods included high-performance liquid chromatography (HPLC) with UV detection, 2,3,7 thin-layer chromatography (TLC) and gas chromatography (GC).…”

Development and validation of a Sensitive bioanalytical method for the quantitative estimation of Pantoprazole in human plasma samples by LC–MS/MS: Application to bioequivalence study

“…Regarding AUC 0-t and C max bioequivalence was assessed by means of analysis of variance (ANOVA) and calculating the standard 90% confidence intervals (90% CIs) of the ratios test/reference (logarithmically transformed data). Bioequivalence was considered when the ratio of averages of log transformed data was within 80-125% for AUC 0-t and C max [10].…”

“…However, the run time of each sample was ∼28 min which is very tedious and time consuming. Nowadays, LC-MS/MS has gained importance for the quantitative estimation of drugs in various biological matrices including plasma, serum, urine, and ocular fluids, due to its high sensitivity, selectivity and reproducibility [9,10]. LC-MS/MS is an analytical tool which combines the physical separation capabilities of liquid chromatography and analytical capabilities of mass spectrometry.…”

Determination of bicyclol in dog plasma using liquid chromatography–tandem mass spectrometry

“…The previous HPLC methods suffer from disadvantages such as narrow linearity range, low sensitivity and time consuming. Nowadays, LC/MS has gained importance for the quantitative estimation of drugs due to its high sensitivity, selectivity and reproducibility [7,8]. Tan et al [9] developed a LC/MS method to determine bicyclol in rat plasma and the limits of detection was 3.3 ng/mL.…”