Pharmacokinetics, urinary excretion and dosage regimen of diminazene in crossbred calves

The pharmacokinetics, urinary excretion and dosage regimen of diminazene we re investigated in crossbred male calves following a single intramuscular d ose (3.5 mg x kg(-1)). Following intramuscular administration, the pharmaco kinetics of diminazene was described with a one-compartment open model. The absorption rate constant and absorption half-life were 9.86 +/- 3.06 h(-1) and 0.121 +/- 0.40 h, respectively. The value of elimination half-life was 107.5 +/- 8.50 h. The apparent volume of distribution was 0.74 +/- 0.07 L x kg(-1). Systemic availability following intramuscular administration was 91.7%. Approximately 65% of the administered dose of diminazene was elimina ted in the urine within 24 h of its intramuscular administration. Diminazen e was bound to plasma proteins to the extent of approximately 32%. The sati sfactory intramuscular dosage regimen of diminazene for calves would be 2.2 4 mg x kg(-1) followed by 1.5 mg x kg(-1) at 7 days.