title: Residue depletion of nitrofuran drugs and their tissue-bound metabolites in channel catfish (Ictalurus punctatus) after oral dosing.
abstract: The depletion of the nitrofuran drugs furazolidone, nitrofurazone, furaltadone, and nitrofurantoin and their tissue-bound metabolites [3-amino-2-oxazolidinone (AOZ), semicarbazide (SC), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), and 1-aminohydantoin (AH), respectively] were examined in the muscle of channel catfish following oral dosing (1 mg/kg body weight). Parent drugs were measurable in muscle within 2 h. Peak levels were found at 4 h for furazolidone (30.4 ng/g) and at 12 h for nitrofurazone, furaltadone, and nitrofurantoin (104, 35.2, and 9.8 ng/g respectively). Parent drugs were rapidly eliminated from muscle, and tissue concentrations fell below the limit of detection (1 ng/g) at 96 h. Peak levels of tissue-bound AMOZ and AOZ (46.8 and 33.7 ng/g respectively) were measured at 12 h, and of SC and AH (31.1 and 9.1 ng/g, respectively) at 24 h. Tissue-bound metabolites were measurable for up to 56 days postdose. These results support the use of tissue-bound metabolites as target analytes for monitoring nitrofuran drugs in channel catfish.
authors.affiliation: Center for Veterinary Medicine, U.S. Food and Drug Administration, 8401 Muirkirk Road, Laurel, Maryland 20708, USA. pak.chu@fda.hhs.gov
authors.forename: Pak-Sin
authors.initials: PS
authors.lastname: Chu
authors.forename: Mayda I
authors.initials: MI
authors.lastname: Lopez
authors.forename: Ann
authors.initials: A
authors.lastname: Abraham
authors.forename: Kathleen R
authors.initials: KR
authors.lastname: El Said
authors.forename: Steven M
authors.initials: SM
authors.lastname: Plakas
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics; D007059:Ictaluridae / Q000378:metabolism*; D007700:Kinetics; D009132:Muscles / Q000737:chemistry* / Q000378:metabolism; D009581:Nitrofurans / Q000008:administration & dosage* / Q000032:analysis / Q000493:pharmacokinetics*
chemical_list: D000890:Anti-Infective Agents; D009581:Nitrofurans