Abstract

The kinetics of tramadol at 3 mg/kg was studied in twenty four local dogs (twelve males and twelve females), after a single intravenous and subcutaneous dose administration. Three milliliters of blood from the jugular vein were collected before and at 2, 5, 10, 15, 30 and 45 min, 1, 1.5, 2, 2.5, 3, 4, 6, 8 and 9 h post administration of tramadol from both groups with the exception of 2 min for subcutaneous group. The collected blood samples were analyzed using a high performance liquid chromatography. In male dogs, the maximum plasma concentration (Cmax) was attained (Tmax) much faster (0.17 h) and systemic bioavailability was higher (29.65±11.7%) than in female dogs with 15.68±4.19%. On the other hand, AUC, t1/2α, t1/2β Vd(ss) were not significantly different between male and  female dogs. These findings suggest the presence of some differences in the kinetics of tramadol between the male and female dogs.

Key words: Tramadol, pharmacokinetics, gender-difference, dogs.