B. Gassner et A. Wuethrich, PHARMACOKINETIC AND TOXICOLOGICAL ASPECTS OF THE MEDICATION OF BEEF-TYPE CALVES WITH AN ORAL FORMULATION OF CHLORAMPHENICOL PALMITATE, Journal of veterinary pharmacology and therapeutics, 17(4), 1994, pp. 279-283
Chloramphenicol (CAP) plasma levels were determined after oral adminis
tration of four doses of CAP palmitate (each dose corresponding to CAP
25 mg/kg/12 h) to four ruminating beef-type calves. Steady-state plas
ma concentrations of CAP were reached after the fourth oral dose and v
aried between 5 and 6 mug/ml. Half-life of elimination of CAP was 4.5
h. In addition to CAP, dehydrochloramphenicol (DH-CAP), a metabolite o
f chloramphenicol, was detected in plasma at concentrations between 3
and 7 ng/ml. DH-CAP is known to be produced from CAP by intestinal bac
teria. This is significant since DH-CAP is suspected of being involved
in the development of fatal aplastic anaemia, which occurs in man aft
er exposure to CAP. Thus, it cannot be excluded that DH-CAP residues m
ay occur in edible tissues. A risk arising from DH-CAP can neither be
excluded for the animals being treated with CAP nor for consumers.