Medycyna Wet. 65 (10), 687-692, 2009
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| Łebkowska-Wieruszewska B., Kowalski C., Saccomanni G., Giorgi M. |
| Pharmacokinetics of tramadol and its major conjugates after a single per os administration of a sustained tablet and per rectum suppositories formulations in dogs |
| The aim of the present study is to evaluate the pharmacokinetics of T and its major metabolites M1, M2 and M5 after the single oral administration of an SR tablet and rectal suppositories in dogs (4-6 mg•kg-1 m.c.). The plasma concentration data after SR-tablet and rectal administration were fitted on the basis of a mono- and non-compartmental model, respectively. T plasma concentration after SR tablet administration was quantitatively detected in three dogs, M1 was quantized in only one dog while M2 and M5 were quantized in all the dogs. T showed median values of Cmax, Tmax and T1/2 of 40 (20-170) ng•mL-1, 3 (4-2) and 1.88 (2.21-1.44) hours, respectively. M5 showed median values of Cmax, Tmax and T1/2 of 0.1 (90-190) ng•mL-1, 2 (3-1) and 4.23 (6.58-1.85) hours, respectively. M2 showed median values of Cmax, Tmax and T1/2 of 220 (80-330) ng•mL-1, 4 (7-3) and 4.49 (6.39-1.57) hours, respectively. Following rectal administration, T was detected from 5 minutes up to 10 h in a smaller amount than M5 and M2. T median value of Cmax was 140±60 ng•mL-1 in 0.56±0.41 h (Tmax). K01 t1/2 and K10 t1/2 were 0.27±0.25 h and 2.24±1.82h, respectively. M1 was detectable from 5 min up to 2 h, showing low values (7-28 ng•mL-1). The present findings suggest oral SR tablet and suppository rectal formulation have similar pharmacokinetic behavior and would not have suitable pharmacokinetic characteristics to be administered once-a-day as an effective and safe treatment for pain in dogs. |
| Key words: tramadol, dog, pharmacokinetic, sustained release tablet, suppositories |