title: Comparison of plasma pharmacokinetics and bioequivalence of ceftiofur sodium in cattle after a single intramuscular or subcutaneous injection.
abstract: Ceftiofur sodium, a broad-spectrum cephalosporin, is active against gram-positive and gram-negative pathogens of veterinary importance. This study was designed to compare the bioequivalence of the sodium salt in cattle after a single intramuscular (i.m.) or subcutaneous dose (s.c.) of 2.2 mg ceftiofur equivalents/kg body weight. The criteria used to evaluate bioequivalence were (1) the area under the curve from time of injection to the limit of quantitation (LOQ) of the assay (AUC0-LOQ), and (2) time concentrations remained above 0.2 microg/mL (t>0.2). Twelve crossbred beef cattle were enrolled in a three-period, two-treatment crossover trial, with a minimum 2-week washout period between doses of 2.2 mg ceftiofur equivalents/kg. Blood samples were collected serially for up to 72 h post-injection. Plasma samples were then analyzed using a validated assay that measures ceftiofur, and all desfuroylceftiofur-related metabolites, by high-performance liquid chromatography (HPLC) as the stable derivative, desfuroylceftiofur acetamide. A maximum plasma concentration (Cmax) of 13.9+/-3.55 microg/mL was observed from 0. 67-2.0 h after i.m. administration, whereas a Cmax of 13.6+/-3.85 microg/mL was observed from 0.67-3.0 h after s.c. administration. The AUC0-LOQ was 108+/-35.0 microg. h/mL after i.m. dosing, compared with 105+/-29.8 microg. h/mL after s.c. dosing. The pre-established criterion for equivalence of the AUC0-LOQ for the i.m. and s.c. routes of administration was satisfied. The t>0.2 was 49.2+/-8.55 h after i.m. administration, compared with 47.0+/-9.40 h after s.c. administration. The pre-established criterion for equivalence of the t>0.2 for i.m. and s.c. administration was satisfied. The equivalence of AUC0-LOQ and t>0.2 for i.m. and s.c. administration of 2.2 mg ceftiofur equivalents (CE)/kg doses of ceftiofur sodium suggest similar therapeutic efficacy and systemic safety for the two routes of administration.
authors: Animal Health Product Development, Pharmacia & Upjohn Company, Kalamazoo, MI 49001, USA. scott.a.brown@am.pnu.com
authors: S A
authors: SA
authors: Brown
authors: S T
authors: ST
authors: Chester
authors: A K
authors: AK
authors: Speedy
authors: V L
authors: VL
authors: Hubbard
authors: J K
authors: JK
authors: Callahan
authors: P J
authors: PJ
authors: Hamlow
authors: B
authors: B
authors: Hibbard
authors: E J
authors: EJ
authors: Robb
mesh_terms: D000818:Animals; D019540:Area Under Curve; D002417:Cattle / Q000378:metabolism*; D002511:Cephalosporins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D007273:Injections, Intramuscular / Q000662:veterinary; D007279:Injections, Subcutaneous / Q000662:veterinary; D008297:Male; D013810:Therapeutic Equivalency
chemical_list: D002511:Cephalosporins; C053503:ceftiofur