Abstract

1. Razuprotafib, a sulphamic acid-containing phosphatase inhibitor, is shown in vivo to undergo enzymatic oxidation and methylation to form a major metabolite in monkey and human excreta with an m/z^– value of 633.

2. LC-MS/MS analysis of samples derived from incubations of razuprotafib with human liver microsomes and recombinant CYP2C8 enzyme has elucidated the metabolic pathway for formation of the thiol precursor to the S-methyl metabolite MS633 (m/z^– 633).

3. Under in vitro conditions, the major pathway of razuprotafib metabolism involves extensive oxidation of the thiophene and phenyl rings.

4. A single oxidation takes place at one of the phenyl groups. Multiple oxidations occur at the thiophene moiety: initial oxidation results in the formation of a thiolactone followed by a second oxidation giving rise to an S-oxide of the thiolactone, which is further metabolised to the ring-opened form and ultimate formation of a thiol (m/z^– 619).

5. An additional mono-oxidation pathway involves epoxidation of the thiophene followed by hydrolysis to a diol.

6. The thiol and diol metabolites are trapped by the addition of a nucleophilic trapping agent, 3-methoxyphenacyl bromide (MPB), giving adducts with m/z^– 767.

7. The thiol is a likely precursor to the major in vivo razuprotafib metabolite, MS633.

摘要

1. Razuprotafib，一个氨基磺酸含酸磷酸酶抑制剂，示出了在体内经历酶促氧化和甲基化，以形成在猴子和人的排泄物主要代谢产物与M / Z ^-的633值。

2. 对来自 razuprotafib 与人肝微粒体和重组 CYP2C8 酶孵育的样品的 LC-MS/MS 分析阐明了形成硫醇前体到 S-甲基代谢物 MS633 ( m/z ^– 633)的代谢途径。

3. 在体外条件下，razuprotafib 代谢的主要途径涉及噻吩和苯环的广泛氧化。

4. 在一个苯基上发生单次氧化。噻吩部分发生多次氧化：初始氧化形成硫内酯，然后第二次氧化产生硫内酯的 S-氧化物，进一步代谢为开环形式并最终形成硫醇。m/z ^– 619）。

5. 另一个单氧化途径涉及噻吩的环氧化，然后水解为二醇。

6. 通过添加亲核捕集剂 3-甲氧基苯甲酰溴 (MPB) 来捕集硫醇和二醇代谢物，得到m/z ^– 767 的加合物。

7. 硫醇可能是体内主要的razuprotafib 代谢物 MS633 的前体。