• Journal of Applied Biological Chemistry
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• v.43 no.1
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• pp.49-53
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• 2000

The in vitro metabolism of a new herbicide pyribenzoxim, {benzophenone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime} was studied using rice, barnyardgrass and rat liver microsomes. No metabolism of pyribenzoxim was observed with rice and barnyardgrass microsomes though the cvtochrome P450 was active, which was evidenced by the metabolism of cinnamic acid. With rat liver microsomes, four metabolites (M1, M2, M3, and M4) were produced while parent compound decreased. M1 and M2 were from the hydrolysis reactions and NADPH-dependent metabolites were M3 and M4 (major metabolite) which were hydroxylated by cytochrome P450. They were identified as bispyribac-sodium (M1), benzophenone oxime (M2), {benzophenone O-[2,6-bis[(5-hydroxy-4,6-dimethoxy-2-pyrimidinyl)oxy]-benzoyl]oxime}(M3), and {benzophenone O-[2[(5-hydroxy-4,6-dimethoxy-2l-pyrimidinyl)6-(4,.6dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime} (M4) through LC/MS/MS analyses. Based on the results obtained metabolic map of pyribenzoxim is proposed.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.

• Analytical Science and Technology
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• v.12 no.3
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• pp.190-195
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• 1999

The metabolism of testosterone ($17{\beta}$-hydroxy-androst-4-en-3-one) was confirmed in horse after a single intramuscular administration of testosterone cypionate (750 mg). Solvent extracts of urine obtained with enzymatic hydrolysis and methanolysis were analyzed by GC/MS after oxime t-butyldimethylsilyl (oxime-TBDMS) derivatization. The structures of four urinary metabolite after testosterone administration in horse were determined based on EI mass spectra and $5{\alpha}$-androstane-$3{\beta}$, $17{\alpha}$-diol and $5{\alpha}$-androstane-$3{\beta}$-ol-17-one as major was confirmed with authentic standard. Also the concentrations of $5{\alpha}$-androstane-$3{\beta}$, $17{\alpha}$-diol, $5{\alpha}$-androstane-$3{\beta}$, $17{\beta}$-diol, dehydroepiandrosterone (DHEA), $5{\alpha}$-androstane-$3{\beta}$-ol-17-one and testosterone were determined in the urine of normal subjects and the urine after administration. The recovery and detection limit in the most drugs were 86.3~94.7% and 1~3 ppb, respectively. Correlation coefficients for calibration were in the range of 0.984~0.999. Excretion profile of testosterone presents the rapid and large increasement up to maximum values at days 5 after administration and the slow regression. The relative ratios of testosterone, its metabolites over DHEA were determined for indication of testosterone administration in horse doping.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4275-4276
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• 2012