Premium
Pharmacokinetics, metabolism and renal clearance of sulphatroxazole in calves and cows
Author(s) -
NOUWS J. F. M.,
VREE T. B.,
MEVIUS D.,
DEGEN M.
Publication year - 1989
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1989.tb00641.x
Subject(s) - metabolite , pharmacokinetics , chemistry , urine , excretion , endocrinology , volume of distribution , metabolism , renal physiology , medicine , renal function , biology , biochemistry
The pharmacokinetic analysis of plasma concentration‐time curves after a single i.v. dose of 20 mg/kg sulphatroxazole (STZ) to calves and cows revealed a small distribution volume of STZ (mean V D(area) = 0.22–0.26 1/kg) and an age dependent elimination (mean t 1/2 6.6–18.8 h). In calves and cows, STZ was extensively metabolized into the N 4 ‐acetyl and 5‐hydroxy derivatives. In the plasma of calves, the N 4 ‐acetyl metabolite (N 4 ‐STZ) was present in greater amounts than the hydroxy metabolite (5‐OH‐STZ), while in cows' plasma concentrations of these two metabolites were similar. In the milk of dairy cows STZ concentrations paralleled those of the metabolites and were approximately 21 times lower than corresponding plasma concentrations. The mean plasma protein binding of STZ and its metabolites ranged from 36.4 to 82.5% of total concentration. The N 4 ‐STZ derivative was excreted by tubular secretion; the 5‐OH‐STZ and the parent compound, mainly by glomerular filtration. In calves the majority of STZ administered was excreted as N 4 ‐STZ (40–52%), while in cows the parent drug dominated the urinary excretion (36%).