title: Bacillus stearothermophilus disk assay for determining ampicillin residues in fish muscle.
abstract: The Bacillus stearothermophilus disk assay for penicillin in milk (AOAC official method) was adapted for the determination of ampicillin in fish muscle. The method was evaluated in 2 species of cultured fish: channel catfish and striped bass. Recoveries of ampicillin ranged from 99 to 104% when muscle specimens from both species were spiked at concentrations of 0.025-1.00 micrograms/g. The lower limit of determination (LOD) was 0.025 micrograms/g. The assay was applied to monitor the elimination of ampicillin from the muscle of striped bass after intravascular administration (dosage of 10 mg/kg body weight). The mean concentrations in the muscle declined from 1.160 micrograms/g at 2 h to 0.063 micrograms/g at 18 h. The half-life of ampicillin in the muscle was 3.6 h. Ampicillin concentrations were below LOD at 24 h. No inhibitory activity was observed in the muscle of control fish.
authors.affiliation: Food and Drug Administration, Fishery Research Branch, Dauphin Island, AL 36528.
authors.forename: S M
authors.initials: SM
authors.lastname: Plakas
authors.forename: A
authors.initials: A
authors.lastname: DePaola
authors.forename: M B
authors.initials: MB
authors.lastname: Moxey
mesh_terms: D000667:Ampicillin / Q000032:analysis* / Q000493:pharmacokinetics / Q000494:pharmacology; D000818:Animals; D001492:Bass; D001681:Biological Assay; D004350:Drug Residues / Q000032:analysis*; D001411:Geobacillus stearothermophilus / Q000187:drug effects / Q000254:growth & development; D007059:Ictaluridae; D009132:Muscles / Q000737:chemistry*
chemical_list: D000667:Ampicillin