Objective—To determine tissue depletion profiles for
gentamicin and its 3 major components (C1, C1a, and
C2) in turkeys.
Animals—Twenty 10-week-old male turkeys.
Procedure—4 birds were maintained as untreated
controls. The remaining birds were treated with gentamicin
sulfate at a dosage of 2 mg/kg, IM, once daily
for 5 days. Treated birds were euthanatized 45, 60, 75,
and 90 days (4 birds at each sample time) after the
last dose of gentamicin was administered, and samples
of muscle, liver, kidney, and skin and fat were collected.
Control birds were euthanatized on day 45.
Concentrations of the 3 major components of gentamicin
were measured by means of reversed-phase
high-performance liquid chromatography.
Results—Total gentamicin concentration (ie, sum of
the concentrations of the 3 major components) was
< 100 µg/kg for all muscle and skin and fat samples by
day 45 and all liver samples by day 75. At all sample
times, concentration of the gentamicin C1 component
was higher than concentrations of the C1a and
C2 components in all tissues.
Conclusions and Clinical Relevance—Results suggest
that tissue depletion profiles of the 3 major components
of gentamicin differ from each other.
Withdrawal time, therefore, may depend on the ratio
of the components in the pharmaceutical preparation
used. (Am J Vet Res 2003;64:1234–1236)