ABSTRACT
A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and validated for simultaneous quantification of sitagliptin and simvastatin in human plasma. Carbamazepine was used as an internal standard (IS). The analytes and IS were extracted from the human plasma by liquid-liquid extraction technique. The reconstituted samples were chromatographed on an Alltima HP C(18) column using an isocratic solvent mixture [acetonitrile-5 mm ammonium acetate (pH 4.5), 85:15 (v/v)] at a flow rate of 1.0 mL/min. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curves obtained were linear (r(2) ≥ 0.99) over the concentration range of 0.10-501 and 0.05-105 ng/mL for sitagliptin and simvastatin, respectively. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. Both the analytes were found to be stable in a battery of stability studies. The method is precise and sensitive enough for its intended purpose. A run time of 3.0 min for each sample made it possible to analyze more than 300 plasma samples per day. The developed assay was successfully applied to a pharmacokinetic study in human volunteers.
Subject(s)
Chromatography, Liquid/methods , Pyrazines/blood , Simvastatin/blood , Tandem Mass Spectrometry/methods , Triazoles/blood , Administration, Oral , Dipeptidyl-Peptidase IV Inhibitors/administration & dosage , Dipeptidyl-Peptidase IV Inhibitors/blood , Dipeptidyl-Peptidase IV Inhibitors/chemistry , Dipeptidyl-Peptidase IV Inhibitors/pharmacokinetics , Drug Stability , Humans , Least-Squares Analysis , Liquid-Liquid Extraction/methods , Male , Pyrazines/administration & dosage , Pyrazines/chemistry , Pyrazines/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Simvastatin/chemistry , Simvastatin/pharmacokinetics , Sitagliptin Phosphate , Triazoles/administration & dosage , Triazoles/chemistry , Triazoles/pharmacokineticsABSTRACT
An analytical method based on liquid chromatographic-tandem mass spectrometry (LC-MS/MS) was developed for the determination of the non-nucleoside reverse transcriptase inhibitor rilpivirine in human plasma using nevirapine as an internal standard. Analyte and the internal standard were extracted from human plasma by liquid-liquid extraction. The reconstituted samples were chromatographed on a C(18) column using a mixture of acetonitrile and 0.1% formic acid buffer (80:20, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The linearity was confirmed in the concentration range 0.51-200 ng/mL in human plasma. Multiple reaction monitoring mode was used for quantification of ion transitions at m/z 367.2/195.1 and 267.1/226.1 for the drug and the internal standard, respectively. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. Extraction recoveries of drug from plasma were >69.5%. A run time of 2.50 min for each sample made it possible to analyze more than 300 plasma samples per day. The developed method is simple, rapid and sensitive for the determination of rilpivirine concentrations in real-time plasma samples obtained from pharmacokinetic studies.
Subject(s)
Chromatography, Liquid/methods , Nitriles/blood , Pyrimidines/blood , Tandem Mass Spectrometry/methods , Drug Stability , Humans , Least-Squares Analysis , Liquid-Liquid Extraction , Male , Nitriles/chemistry , Nitriles/pharmacokinetics , Pyrimidines/chemistry , Pyrimidines/pharmacokinetics , Reproducibility of Results , Rilpivirine , Sensitivity and SpecificityABSTRACT
To investigate the profile of paracetamol (CAS 103-90-2, Calpol) metabolism in Indian population and to compare with the profiles of studies conducted in other populations, a study was conducted in 100 healthy male human volunteers. After an overnight fast, the volunteers were administered an oral dose of 1 g of paracetamol, urine was collected up to 8 h and samples were analyzed by high performance liquid chromatography for the estimation of urinary recovery of paracetamol and its metabolites, i.e. sulphate, glucuronide, cysteine and mercapturate conjugates. 25.29 +/- 5.5 (mean +/- S.D.)% of sulphate conjugate, 60.55 +/- 8.5% of glucuronide conjugate, 5.05 +/- 2.1% of unchanged paracetamol, 2.76 +/- 2.4% of cysteine conjugate and 6.37 +/- 3.8% of mercapturate conjugate were recovered. The mean combined recovery of glutathione conjugates (9.13%) in Indians is found to be very high and is equal to that in Caucasians of Scotland (9.3%), which indicates that Indians are equally predisposed to hepatotoxicity as Caucasians.
