title: Cambendazole and nondrug macromolecules in tissue residues.
abstract: The anthelmintic cambendazole is rapidly metabolized to at least 13 urinary metabolites. Radioactivity was found in liver for weeks after a single dose in cattle, but even at 3 days' withdrawal, cambendazole and metabolites previously identified in urine accounted for only a small fraction of liver radioactivity. The radioactivity was ubiquitously distributed in protein and nucleic acid fractions, and [14C] glutamic acid was identified, indicating incorporation of 14C into the endogenous pool. Part of the residual liver radioactivity at 7 days was convertible chemically to 5-nitrobenzimidazole, indicating a drug-related macromolecular residue. However, data from rats fed radiolabeled steer liver indicate that the residue is minimally bioavailable and therefore of substantially less toxicological concern than cambendazole itself.
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000378:metabolism*; D001682:Biological Availability; D002159:Cambendazole / Q000032:analysis / Q000138:chemical synthesis / Q000378:metabolism*; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D005971:Glutamates / Q000378:metabolism; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D012756:Sheep; D013997:Time Factors
chemical_list: D001562:Benzimidazoles; D005971:Glutamates; D002159:Cambendazole