Simultaneous quantitation of the BACE1 inhibitor AZD3293 and its metabolite AZ13569724 in human matrices by LC-MS/MS.

Aim: AZD3293 is a novel BACE1 inhibitor in Phase III development for Alzheimer's disease. Sensitive and robust bioanalytical methods were required to quantitate AZD3293 and its metabolite AZ13569724 in human biological matrices. Methodology/results: Human plasma was prepared by protein precipitation. Linearity for both analytes was in the range of 0.5-500 ng/ml with up to 100-fold dilution. Plasma ultrafiltrate samples were prepared using Centrifree (R) ultrafiltration device. Urine and CSF samples were analyzed directly after dilution. A 27% decrease in AZD3293 concentrations in the CSF collection apparati was found due to nonspecific binding. Incurred sample reanalysis was acceptable. Conclusion: Methods for simultaneous quantitation of AZD3293 and its metabolite AZ13569724 in human biological matrices have been validated and successfully applied to clinical studies.