title: Conversion of cephapirin to deacetylcephapirin in milk and tissues of treated animals.
abstract: Cephapirin is one of six beta-lactam antibiotics approved for use in the treatment of food-producing animals in the United States. When used for treatment of mastitis by intramammary infusion, it is partially converted to a microbiologically active metabolite identified as deacetylcephapirin (DACEP). The degradation was followed in four cows with naturally acquired mastitis which were treated with cephapirin. DACEP persisted longer than the parent compound in the milk. When a calf was treated with cephapirin by intramuscular injection, the compound was almost completely converted to DACEP in tissues. The deacetyl form must be considered in the determination of residues in treated animals.
authors.affiliation: Food Animal Protection Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, College Station, Texas 77845, USA. wmoats@lpsi.barc.usda.gov
authors.forename: W A
authors.initials: WA
authors.lastname: Moats
authors.forename: K L
authors.initials: KL
authors.lastname: Anderson
authors.forename: J E
authors.initials: JE
authors.lastname: Rushing
authors.forename: S
authors.initials: S
authors.lastname: Buckley
mesh_terms: D000818:Animals; D002417:Cattle; D002511:Cephalosporins / Q000378:metabolism* / Q000627:therapeutic use; D002514:Cephapirin / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000627:therapeutic use; D002853:Chromatography, Liquid; D005260:Female; D007668:Kidney / Q000737:chemistry; D008414:Mastitis, Bovine / Q000188:drug therapy; D008892:Milk / Q000378:metabolism*; D009132:Muscles / Q000737:chemistry
chemical_list: D002511:Cephalosporins; D002514:Cephapirin; C049805:desacetyl cephapirin