Effective screening approach to select esterase inhibitors used for stabilizing ester-containing prodrugs analyzed by LC-MS/MS.

BACKGROUND Analysis of prodrugs, with their short half-lives, especially ester-containing ones, poses a unique challenge in developing and validating bioanalytical assays for nonclinical and clinical studies. A screening approach is needed to expeditiously select esterase inhibitors for stabilizing them during sample collection and processing. RESULTS The screening process consisted of three steps. Initially, nine different esterase inhibitors were screened at three different plasma concentrations against an ester prodrug. Four inhibitors were chosen for the next step, in which plasma pH and processing temperature were optimized. Finally, whole-blood stability of the prodrug was evaluated. Three inhibitors with optimized plasma pH and processing temperature were selected for further bioanalytical assay development. CONCLUSION An effective approach was successfully developed to promptly select suitable esterase inhibitors for stabilizing ester-containing prodrugs.