A novel LC-MS/MS method for simultaneous estimation of acalabrutinib and its active metabolite acalabrutinib M27 in human plasma and application to a human pharmacokinetic study.

A simple, specific, selective and accurate bioanalytical method was developed and validated for simultaneous estimation of acalabrutinib and its active metabolite in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Deuterated analogs of both the analytes were used as internal standards. The extraction of analytes and internal standards were evaluated from the human plasma by liquid-liquid extraction technique using methyl tertiary butyl ether (TBME). The separation of the analytes was carried out on Zorbax Eclipse XDB-C18 (150 × 4.6 mm, 5 µm) column with a mixture of acetonitrile and 10 mM ammonium formate in 0.1% formic acid buffer (65 : 35, v/v) as mobile phase at a flow rate of 1 mL min-1. The method linearity was determined in the widen concentration range from 5.000 ng mL-1 to 1600 ng mL-1 with r 2 > 0.99. The entire method validation was carried out as per the USFDA guidelines on bioanalytical method validation and all validation experiment results were found within acceptable limits. Clinical pharmacokinetic study of both the parent drug and its active metabolite was successfully performed on six healthy volunteers under fasting conditions by applying the present method.

A novel LC-MS/MS method for simultaneous estimation of obeticholic acid, glyco-obeticholic acid, tauro-obeticholic acid in human plasma and its application to a pharmacokinetic study.

A rapid, robust, simple, selective, and sensitive liquid chromatography-tandem mass spectrometry method was developed for the simultaneous estimation of obeticholic acid and its two pharmacologically active metabolites, glyco-obeticholic acid, and tauro-obeticholic acid in human plasma. The analytes and their heavy stable isotope-labeled internal standards were extracted from 250 µL human plasma by a solid-phase extraction technique. The method linearity was established over a concentration range of 0.410 to 120.466 ng/mL for obeticholic acid, 0.414 to 121.708 ng/mL for glyco-obeticholic acid, and 0.255 to 75.101 ng/mL for tauro-obeticholic acid. The method was fully validated as per current guidelines on bioanalytical method validation of "United States of Food and Drug Administration" and "European Medicines Agency." The method was successfully applied to study the pharmacokinetics of obeticholic acid, glyco-obeticholic acid, and tauro-obeticholic acid following oral administration of obeticholic acid tablets to healthy male volunteers. All the measured concentrations were within calibration curve ranges.