Development and validation of bioanalytical method for quantification of cycloserine in human plasma by liquid chromatography-tandem mass spectrometry: Application to pharmacokinetic study.

A selective, sensitive and high-throughput liquid chromatography-tandem mass spectrometry bioanalytical method has been developed for the estimation of cycloserine in human plasma, employing cytosine as the internal standard. The extraction of the analyte was facilitated by solid-phase extraction using 100 μL of human plasma. The separation was carried out on a BDS Hypersil C (150 × 4.6 mm, 5 μm) column using a mixture of 0.2% formic acid in HPLC-grade water, methanol and acetonitrile (70:15:15, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The method was linear over the range of 0.20-20 μg/mL with r  > 0.99. Complete validation of the method was performed as per US Food and Drug Administration guidelines and the results met acceptance criteria. Applying the present method, the clinical pharmacokinetics of cycloserine following oral administration of 250 mg cycloserine was studied under fasting conditions. Assay reproducibility was also verified by incurred sample reanalysis.