A fast, sensitive, and high throughput method for the determination of esomeprazole in dog plasma by UHPLC-MS/MS: Application to formulation development of the compound preparation of esomeprazole

To investigate deeply into the preclinical pharmacokinetics and prescription design of esomeprazole, a sensitive, high throughput and robust UHPLC-MS/MS method had been developed and fully validated for the analysis of esomeprazole in dog plasma. Esomeprazole and diazepam (IS) were fast extracted from plasma by alkalified organic solvent, and separated on MP-C-18 column with methanol and 0.1% formic acid. The quantification of esomeprazole and IS had been achieved using fragmentation transitions of m/z 346.1 -> 198.1 and m/z 285.0 -> 193.2 in MRM detection under positive ESI mode. The concentration of esomeprazole in dog plasma was linear with the range of 3.75-500 ng/mL. The precisions of intra- and inter-day were no more than 11.6%, while the accuracies were all within +/- 9.7% of the nominal values. The recovery was no more than 77.06%, and the matrix effect, stability, dilution integrity tests were all satisfied the currently criterion. Then the method was successfully performed to evaluating pharmacokinetics of esomeprazole and optimizing the prescription of modified esomeprazole with varied addition of sodium bicarbonate. Consequently, a pharmacokinetic study of three doses esomeprazole with the optimized addition of sodium bicarbonate in dogs has been successfully researched for the first time. It could be a promising approach to improve the stabilization of acid-labile esomeprazole and would provide a useful reference for the formulation design of esomeprazole.