Isolation and identification of a major metabolite of PNU-107859, an MMP inhibitor from the biliary fluid of rats.

PNU-107859, an important representative structure in a novel class of matrix metalloproteinases (MMP) inhibitors known as thiadiazoles, was found to be quickly eliminated from rats. A major metabolite (approximately 10% of total dose) was found to be present in the bile of rats. The metabolite in question was isolated and purified from the bile fluids collected from six cannulated rats. From a total of approximately 75 mg of PNU-107859 administered to rats, 3.3 mg of the metabolite was recovered. The NMR and mass spectrometry results indicated that the metabolite is a glucuronide conjugate (1-deoxy-1beta-substituted D-glucopyranosiduronic acid) of the intact drug. Furthermore, the UV, MS, and NMR data established that the conjugate is located at the nitrogen alpha to the thiocarbonyl of the thiadiazole ring.