Validation of LC-MS/MS methods for quantitative analysis of kynurenine pathway metabolites in human plasma and cerebrospinal fluid.

Background: Dysregulation of the kynurenine metabolic pathway has been reported in several neurological conditions. Methods & results: Sensitive and selective LC-MS/MS methods have been validated for six kynurenine pathway metabolites in human cerebrospinal fluid and plasma. For each matrix, we validated three methods - one for the simultaneous determination of kynurenine, kynurenic acid, anthranilic acid and 3-hydroxy-kynurenine (four-analyte assay), one for quinolinic acid and one for tryptophan - using stable-isotopically labeled internal standards. The dynamic range and quantitation limits were based on endogenous concentrations for each analyte. Conclusion: The use of validated methods for kynurenine pathway metabolites in human cerebrospinal fluid and plasma will provide definitive information in neurological diseases.

Development and validation of bioanalytical methods to support investigations of AZD9496 in the clinic.

Aim: AZD9496 is an oral nonsteroidal, potent and selective antagonist and degrader of ER-α. Two major active metabolites (M3 and M5 as diastereomers) were identified in humans. Methodology/results: Multianalyte, sensitive LC-MS/MS method in human plasma was developed and validated that overcame the challenges encountered. The method demonstrated acceptable precision, accuracy and selectivity for AZD9496 and two major metabolites. Incurred sample reanalysis was acceptable from evaluation in clinical studies, indicating adequate reproducibility. In addition, a urine method for AZD9496 was also developed and validated. Conclusion: Robust and sensitive LC-MS/MS assays for the quantitation of AZD9496 and two diastereomeric metabolites in human plasma and AZD9496 in human urine have been validated and successfully applied to clinical studies.