Analysis of primary metabolites of ranolazine in dog urine by LC-MSⁿ

Ranolazine and metabolites in dog urine were identified by LC-MSⁿ.  Dog urine samples were collected after ig 30 mg·kg⁻¹ ranolazine, then the samples were enriched and purified through solid-phase extraction cartridge.  The purified samples were analyzed by LC-MSⁿ .  The possible metabolites were discovered by comparing the full scan and SIM chromatograms of the test samples with the corresponding blanks.  Seventeen phase I metabolites and fourteen phase II metabolites were identified in dog urine.  Three metabolites were identified by comparing with the control article.  The metabolites were formed via the following metabolic pathways: O-demethylation, O-dearylation, hydroxylation, N-dealkylation, amide hydrolysis, glucuronidation and sulfation.  The LC-MSⁿ method is suitable for the rapid identification of drug and its metabolites in biologic samples.