Stabilization of zeylenone in rat plasma by the presence of esterase inhibitors and its LC‐MS/MS assay for pharmacokinetic study

Abstract

Six esterase inhibitors, namely EDTA·2Na(+), NaF, phenylmethanesulfonyl fluoride, dichlorvos, bis-nitrophenyl phosphate (BNPP) and thenoyltrifluoroacetone, and the mixture of NaF and BNPP, were evaluated for the stabilization of labile benzoate containing zeylenone in rat plasma. The mixture appeared to exhibit the most effectively stabilizing effect with the degraded content of zeylenone decreasing from >60% (in the absence of inhibitors) to <6%. Following the stabilization by the addition of NaF (5 mM) and BNPP (5 mM), the analytes in rat plasma were acidified by formic acid and extracted into ethyl acetate at 0°C. After chromatographic separation, the detection of zeylenone was performed on a 3200 Q-Trap with positive ion electrospray mode, monitoring the ion transition m/z 383.2 → 105.0. The method was validated over the range from 2.68 to 1340 ng/mL with inter- and intra-run precision for the quality control samples being less than 6.8%. The assay accuracy was within 100 ± 7.0%. The validated method was successfully applied to a pharmacokinetic study in rats after the intratracheal administration of zeylenone in free drug or polymeric micellar solutions. The results showed that the pulmonary absorption of zeylenone loaded in micelles was significantly retarded compared with that of free drug solutions.

Determination of (-)-epigallocatechin-3-gallate octaacetate and its metabolites in plasma of rats for pharmacokinetic study by ultra-performance-liquid-chromatography coupled to quadrupole-time-of-flight-mass-spectrometry

“…The plasma sample was then mixed with formic acid which inhibited enzymatic reactions. We have tested different types of non-toxic esterase inhibitors at concentrations higher than other reports ( Wei et al, 2013 ; Cai et al, 2018 ; Bhuket et al, 2019 ) by 3–30 folds. We used BNPP and dichlorvos, carboxylesterase inhibitors; TLCK, serine hydrolase inhibitors; Pefabloc, carboxylesterase and serine hydrolase inhibitor; NaF, non-specific inhibitor ( Bhuket et al, 2019 ), but none of them were comparable with formic acid in inhibitory efficiency and reproducibility.…”

Zeylenone represses the progress of human prostate cancer by downregulating the Wnt/β‑catenin pathway

“…The continuous metastasis and proliferation of PCa cells are important clinical features and a principal cause of mortality in the advanced stage of this cancer ( 22 , 23 ). It was demonstrated that Zey demonstrates cytotoxicity to tumor cells ( 10 , 24 ). Similar to previous studies ( 8 , 9 ), the present study demonstrated that Zey decreased the viability of DU145 cells.…”