Oxidative metabolism of razuprotafib (AKB-9778), a sulfamic acid phosphatase inhibitor, in human microsomes and recombinant human CYP2C8 enzyme

Monooxygenase- and Dioxygenase-Catalyzed Oxidative Dearomatization of Thiophenes by Sulfoxidation, cis-Dihydroxylation and Epoxidation

Enzymatic oxidations of thiophenes, including thiophene-containing drugs, are important for biodesulfurization of crude oil and drug metabolism of mono- and poly-cyclic thiophenes. Thiophene oxidative dearomatization pathways involve reactive metabolites, whose detection is important in the pharmaceutical industry, and are catalyzed by monooxygenase (sulfoxidation, epoxidation) and dioxygenase (sulfoxidation, dihydroxylation) enzymes. Sulfoxide and epoxide metabolites of thiophene substrates are often unstable, and, while cis-dihydrodiol metabolites are more stable, significant challenges are presented by both types of metabolite. Prediction of the structure, relative and absolute configuration, and enantiopurity of chiral metabolites obtained from thiophene enzymatic oxidation depends on the substrate, type of oxygenase selected, and molecular docking results. The racemization and dimerization of sulfoxides, cis/trans epimerization of dihydrodiol metabolites, and aromatization of epoxides are all factors associated with the mono- and di-oxygenase-catalyzed metabolism of thiophenes and thiophene-containing drugs and their applications in chemoenzymatic synthesis and medicine.

The in vivo disposition of subcutaneous injected 14C-razuprotafib (14C-AKB-9778), a sulphamic acid phosphatase inhibitor, in nonclinical species and human

The disposition of radioactivity following subcutaneous ¹⁴C-razuprotafib, a Tie2 activator, was explored in multiple species.The absorption and clearance of razuprotafib and total radioactivity in human plasma are rapid and pharmacokinetics support razuprotafib as primary circulating component. Radioactivity is distributed greater to human plasma than whole blood (B:P = 0.36).In pigmented rats, radioactivity distributes to whole-body tissues rapidly and, within 24 h, is localised to elimination pathway end organs and injection site.Overall recovery of radioactivity across species is >93%, with the majority recovered within 24-48 h, and >80% in faeces.The CYP2C8 enzyme contributes significantly to razuprotafib metabolism.A hydrolysis product of razuprotafib (m/z^- 380) is the main component in rat plasma at 2 h (49% peak area radioactivity), while razuprotafib (m/z^- 585) is the main component in plasma for dog (58%), monkey (99.3%), and human (100%).Razuprotafib is present in dog, monkey, and human faeces, with the greatest percentage of radioactivity as metabolites. The major metabolite (>25%) in monkey and human, m/z^- 633, is an S-methylated oxidised derivative of razuprotafib and is localised in faeces.Overall disposition of ¹⁴C-razuprotafib in human is best modelled by monkey over lower order species.