title: Pharmacokinetics of erythromycin in nonlactating and lactating goats after intravenous and intramuscular administration.
abstract: The objectives of this work were to compare the pharmacokinetics of erythromycin administered by the intramuscular (i.m.) and intravenous (i.v.) routes between nonlactating and lactating goats and to determine the passage of the drug from blood into milk. Six nonpregnant, nonlactating and six lactating goats received erythromycin by the i.m. (15 mg/kg) and the i.v. (10 mg/kg) routes of administration. Milk and blood samples were collected at predetermined times. Erythromycin concentrations were determined by microbiological assay. Results are reported as mean +/- SD. Comparison of the pharmacokinetic profiles between nonlactating and lactating animals after i.v. administration indicated that significant differences were found in the mean body clearance (8.38 +/- 1.45 vs. 3.77 +/- 0.83 mL/kg x h respectively), mean residence time (0.96 +/- 0.20 vs. 3.18 +/- 1.32 h respectively), area under curve from 0 to 12 h (AUC(0-12)) (1.22 +/- 0.22 vs. 2.76 +/- 0.58 microg x h/mL respectively) and elimination half-life (1.41 +/- 1.20 vs. 3.32 +/- 1.34 h); however, only AUC(0-12) showed significant differences after the i.m. administration. Passage of erythromycin in milk was high (peak milk concentration/peak serum concentration, 2.06 +/- 0.36 and AUC(0-12milk)/AUC(0-12serum),6.9 +/- 1.05 and 2.37 +/- 0.61 after i.v. and i.m. administrations respectively). We, therefore, conclude that lactation affects erythromycin pharmacokinetics in goats.
authors.affiliation: Cátedra de Farmacología, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina. ambros@fvet.uba.ar
authors.forename: L
authors.initials: L
authors.lastname: Ambros
authors.forename: L
authors.initials: L
authors.lastname: Montoya
authors.forename: V
authors.initials: V
authors.lastname: Kreil
authors.forename: S
authors.initials: S
authors.lastname: Waxman
authors.forename: G
authors.initials: G
authors.lastname: Albarellos
authors.forename: M
authors.initials: M
authors.lastname: Rebuelto
authors.forename: R
authors.initials: R
authors.lastname: Hallu
authors.forename: M I
authors.initials: MI
authors.lastname: San Andres
mesh_terms: D000818:Animals; D019540:Area Under Curve; D018592:Cross-Over Studies; D004917:Erythromycin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D006041:Goats / Q000378:metabolism*; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D007774:Lactation; D008892:Milk / Q000378:metabolism*
chemical_list: D004917:Erythromycin