The metabolism of methazolamide - identification of metabolites in guinea pig urine

The in vivo metabolism of methazolamide, a carbonic anhydrase inhibitor, was studied using guinea pigs as the animals. (14)C-Labeled methazolamide was synthesized. Eighty percent of intraperitoneally injected radioactivity was recovered from urine and feces within 24 hours. HPLC analysis on a C(18) column detected 2 radioactive metabolites (Peaks A and B). The Peaks A and B were isolated from the urine of the animals dosed with non-radioactive methazolamide.They were purified on the C(18) column. Their chemical structure was revealed by UV-absorbance spect a and LC/MS, and confirmed by comparing it with that of chemically synthesized compound. They were a glucuronide, (2-acetylimino-3-methyl-Δ(4)-1,3,4-thiadiazol-5-yl)-1-thio-β-D-glucopyranosiduronic acid, and a sulfonic acid, N-[3-methyl-5-sulfo-1,3,4-thiadiazol-2(3H)-ylidene]acetamide.