Plasma pharmacokinetics and muscle residue dynamics of mebendazole in Carassius auratus.

Mebendazole is approved for use in aquatic animals and is widely used in Chinese aquaculture. We developed a pharmacokinetic and residue analysis for mebendazole levels in the goldfish (Carassius auratus). Plasma and muscle samples of C. auratus were taken after oral administration of 10 mg/kg mebendazole. The maximal drug plasma concentration of 0.55 mg/L was achieved at 48 hr and then declined with the elimination half-life (T1/2β ) of 7.99 hr. Administration of 10 mg/kg by oral gavage for 5 successive days resulted in a peak mebendazole concentration of 0.70 mg/kg in muscle at 96 hr after the last dose. The drug was then eliminated at a relatively slow rate from muscle with T1/2β of 68.41 hr. There was no detectable mebendazole in any muscle samples at 24 days postadministration. The AUClast in plasma and muscle was 19.42 and 105.33 mg hr/L, respectively. These data provide information for dosage recommendations and withdrawal time determinations for mebendazole use in aquariums.