The activity of mixed function oxidases, estimated by in vivo antipyrine clearance, is similar in horses and camels.

The activity of hepatic mixed function oxidases was compared in horses and camels (Camelus dromedarius) by studying the pharmacokinetics of antipyrine in seven camels and five horses following intravenous administration of a single dose of antipyrine (25 mg/kg). The data obtained (mean +/- SEM and median in brackets) in camels and horses, respectively, were as follows: the elimination half-lives were 3.25 +/- 0.23 (3.19) and 3.09 +/- 0.25 (2.90) hr; the apparent volumes of distribution (area method) were 0.691 +/- 0.045 (0.648) and 0.642 +/- 0.034 (0.676) l/kg; the volumes of distribution at steady state were 0.659 +/- 0.040 (0.607) and 0.620 +/- 0.030 (0.653) l/kg; the volume of the central compartment of the two-compartment pharmacokinetic model were 0.386 +/- 0.0523 (0.349) and 0.298 +/- 0.05 (0.308) l/kg; total body clearances were 0.148 +/- 0.008 (0.158) and 0.145 +/- 0.007 (0.147) l/kg/hr; the areas under the curves to infinity were 171.0 +/- 9 (165) and 175 +/- 8.0 (170) micrograms.ml.hr. There was no statistical significance in any parameter between camels and horses which suggests that the activity of hepatic mixed function oxidases is similar in horses and camels.