Metabolism of Papaverine I. Identification of Metabolites in Rat Bile

1. After hydrolysis with glusulase of bile from rats treated with papaverine, four metabolites (A, B, C and D) were separated.

2. The structures of A, B and C were established as the monodemethylated compounds, 4′-desmethyl-, 7-desmethyl-, and 6-desmethylpapaverine, respectively.

3. D was formed from papaverine by bis-demethylation. Since it was found in cat bile after administering either A or C, but not B, it was identified as 4′,6-desmethylpapaverine.