Objective-To characterize the pharmacokinetics of diminazene in plasma
and pseudo-afferent lymph of East Africa x Galla goats. Design-The ef
ferent prescapular lymphatic duct of 3 goats was cannulated 8 weeks af
ter surgical removal of the lymph node. Thereafter, 3.5 mg of diminaze
ne base/kg of body weight was administered to these goats and to 3 non
cannulated goats. Procedure-Using high-performance liquid chromatograp
hy, concentration of diminazene was determined in plasma and lymph col
lected up to 96 hours after treatment. Results-Maximal concentrations
of diminazene in plasma of noncannulated goats (median [range], 4.30 [
4.28 to 5.01] mu g/ml), plasma of cannulated goats (3.94 [2.94 to 4.06
] mu g/ml), and lymph (1.06 [0.73 to 1.86] mu g/ml) were significantly
different (P < 0.05); values in lymph were considerably lower than th
ose in plasma from noncannulated and cannulated animals. Time to reach
maximal concentration did not differ significantly between lymph and
plasma of noncannulated and cannulated goats. Over the first 24 hours
after drug administration, concentration of diminazene in plasma of no
ncannulated goats was generally higher than that in lymph, but thereaf
ter was similar. Apparent volume of distribution of diminazene in the
plasma of noncannulated (2.57 [1.93 to 2.60] L/kg) and cannulated (2.3
0 [1.04 to 2.40] L/kg) goats did not differ significantly. Penetration
ratio of diminazene into lymph, compared with plasma, of cannulated g
oals was 1.69:1. Conclusions-Disposition of diminazene in goats is cha
racterized by higher concentration in plasma than in lymph. However, t
he drug persists longer in lymph than in plasma. Clinical Relevance-Th
e longer persistence of diminazene in lymph than in plasma may account
for the enhanced therapeutic efficacy of diminazene in the early stag
e, compared with later stages, of a tsetse fly-transmitted trypanosome
infection.