Liquid Chromatographic Multicomponent Method for Determination of Residues of Ipronidazole, Ronidazole, and Dimetridazole and Some Relevant Metabolites in Eggs, Plasma, and Feces and Its Use in Depletion Studies in Laying Hens

Abstract

Abstract A simple, rapid liquid chromatographic (LC) method that uses UV/VIS detection has been developed for the determination In eggs of residues of the hlstomonostats dlmetridazole (DMZ), ronldazole (RON), Ipronidazole (IPR), and side-chain hydroxylated metabolites of DMZ and RON. Sample pretreatment Includes an aqueous extraction, purification with an Extrelut® cartridge, and acid partitioning with Isooctane. An aliquot of the final aqueous extract Is Injected Into a reversephase LC system; detection Is performed at 313 nm. The limits of determination are in the 5-10 µgkg range. A UV/ VIS spectrum can be obtained at the 10 µg/kg level by using diode-array UV/VIS detection. Recoveries are between 80 and 98% with a coefficient of variation of about 5%. Some 20 samples can be analyzed per day. A side-chain hydroxylated metabolite of IPR can also be detected with this method, as demonstrated with samples from animal experiments. After a single oral dose of the drugs to laying hens, residues of the parent compound and/or the hydroxylated metabolites could be detected In eggs 5-8 days after dosing. Plasma distribution and excretion in feces were established both with and without deconjugatlon. DMZ and IPR were extensively metabolized to hydroxylated nltrolmldazole metabolites; RON was excreted mainly as the parent compound.