Human UDP-glucuronosyltransferase UGT1A4 forms tertiary N-glucuronides predominately with the energetically less favored tautomer of substituted 1H-indazole (benzpyrazole)

Background Human UDP-glucuronosyltransferase UGT1A4 is reported to convert a range of tertiary amine substrates to the respective quaternary glucuronides. In this study, we report on the in vitro glucuronidation of a substituted 1H-indazole (benzpyrazole), a transient receptor potential ankyrin 1 antagonist.