Distribution of oxytetracycline in the genital tract of cows
Bretzlaff, K.N.; Ott, R.S.; Koritz, G.D.; Lock, T.F.; Bevill, R.F.; Shawley, R.V.; Gustafsson, B.K.; Davis, L.E.
American Journal of Veterinary Research 43(1): 12-16
1982
ISSN/ISBN: 0002-9645 PMID: 7091807 Document Number: 188144
Pharmacokinetic parameters of the disposition of oxytetracycline (OTC) were investigated in healthy cycling dairy cows after a single IV dose of 22 mg/kg of body weight. The biological half-life of OTC was 6.5 hours. These data were used to predict an IV priming dose and a rate of constant IV infusion of OTC sufficient to approach steady-state equilibrium of the drug between a plasma concentration of approximately 5 microgram/ml and a uterine tissue concentration. After 8 hours' constant IV infusion, the mean plasma concentration of OTC was 4.86 +/- 0.68 microgram/ml and the mean uterine tissue concentration of OTC was 4.50 +/- 0.45 microgram/ml. The mean ratio of plasma-to-uterine tissue OTC concentrations was 1.08. Computer-stimulated IV multiple doses of OTC at 11 mg/kg every 12 hours and 11 mg/kg every 24 hours suggested that the former dosage regimen could provide uterine tissue concentrations greater than 5 microgram/ml during the dosage interval, whereas the latter could provide such concentrations for only the first 12 hours of a 24-hour dosage interval.