Pharmacokinetics of tramadol administered by intravenous and intramuscular routes to female dogs submitted to ovariohysterectomy

Abstract

The objective of the present study was to implant a method using a sensitive and specific system, and validate the whole analytical method to obtain an efficient tool for analyses of tramadol in plasma dogs, and to evaluate the pharmacokinetics of tramadol following intravenous (i.v.) and intramuscular (i.m.) administration of this drug in females dogs submitted to castration. The pharmacokinetics of tramadol were examined following i.v. or i.m. tramadol administration to five female dogs in each group submitted to ovariohysterectomy (dosage=2 mg/kg). In relation to intravenous administration, the half-time for the distribution process (t1/2d = 0.18 ± 0.12 h); the total body clearance was 0.60 ± 0.50 L/h/kg, half-life of elimination (t1/2²) was 1.24 ± 0.69 h. Statistically differences between parameters obtained after i.v. and i.m. was significant only to AUC0[i: 3362.07 ± 1008 and 1604.55 ± 960.02 (ng.h/mL), respectively. The F was 48.00 ± 43.30%. The assay for tramadol described has been demonstrated to meet all requirements for clinical PK studies. In particular, the method has satisfactory specificity, linearity, accuracy and precision range over the concentration examined.