Effect of age on pharmacokinetics of danofloxacin in egyptian buffalo calves

Abstract EN

The pharmacokinetic profile of danofloxacin, a fluoroquinolone antibacterial was studied in one, two-months and one year old Egyptian buffalo calves following a single intravenous and intramuscular administration of 1.25 mg kg-1 b.wt.

in a cross over study with 15-day wash out period.

Drug concentrations in serum were determined by microbiological assay technique.

After i.v administration the serum concentration-time curve of danofloxacin was best fitted using two-compartment open model.

The drug was rapidly distributed as indicated by short distribution half-lives (t½(?)) of 0.093, 0.117 and 0.194 h in one , two-months and one year old calves, respectively.

The elimination half-life was relatively longer in one- and two-months than in one year old calves (t½(?)) 5.802 compared to 4.941 and 3.795 h., respectively.

The volumes of distribution at steady-state (Vdss) 1.259, 1.347 and 1.490 L kg-1), total body clearance (ClB)= 0.155, 0.195 and 0.280 L kg-1 h-1) and mean residence time (MRT = 8.127, 6.886 and 5.334 h) were recorded in the three ages, respectively.

Ara under the plasma concentration vs.

time curve(AUC) was decreased with age 8.564, 6.651 and 4.615 ug ml-1 h-1 in the three ages, respectively).

Following intramuscular administration, the absorption half-life (t½(ab)) was 0.421, 0.462 and 0.425 h in the three ages, respectively.

The maximum serum concentrations (Cmax) of 0.541, 0.434 and 0.363 ug ml-1 were attained after (tmax) 1.853, 1.810 and 1.712 h in the three ages, respectively.

The elimination half-life (t½(el)) and MRT values of danofloxacin were longer in one-month old calves compared to two months and one year old calves.

The systemic intramuscular bioavailabilities were 96.672, 98.136 and 94.366 %, while the in-vitro serum protein-binding tendencies were 6.678, 9.176 and 13.572 %, for one, two- months old and one year old calves, respectively.