Table 1.
Summary of pimobendan and O-demethylated-metabolite pharmacokinetic parameters (mean ± SD) for a single dose of pimobendan in dogs.
| Pimobendan PO | Pimobendan PR | P-value (PO vs. PR) | ||||
|---|---|---|---|---|---|---|
| Parameter | PIM | ODMP | PIM | ODMP | PIM | ODMP |
| Cmax (ng/ml) | 49.1 ± 28.7 | 30.9 ± 10.4 | 10.1 ± 2 | 8.8 ± 4.8 | 0.002 | 0.0001 |
| Cmin (ng/ml) | 2.5 ± 1.4 | 2.8 ± 1.1 | 1.7 ± 0.9 | 1.7 ± 0.5 | ND | ND |
| C12 (ng/ml) | 2.4 ± 1.6 | 5.2 ± 2.5 | 1 | 3.1 ± 1.3 | ND | ND |
| Tmax (h) | 2.1 ± 0.9 | 3.2 ± 1.6 | 1 ± 0.4 | 1.7 ± 1.1 | 0.01 | 0.01 |
| t1/2 (h) | 1.8 ± 0.8 | 5.0 ± 2.7 | 2.2 ± 0.6 | 8.3 ± 4.8 | >0.05 | >0.05 |
| AUC (ng*h/ml) | 148.4 ± 71.6 | 167.8 ± 36.2 | 31.1 ± 11.9 | 50.1 ± 19.2 | 0.03 | 0.0006 |
| MRT (h) | 3.9 ± 1.3 | 8.3 ± 3.5 | 3.5 ± 0.9 | 13.2 ± 8.0 | >0.05 | >0.05 |
| CL/F (ml/h/kg) | 0.004 ± 0.002 | 0.003 ± 0.001 | 0.012 ± 0.003 | 0.010 ± 0.005 | ND | ND |
| V/F (ml/kg) | 0.011 ± 0.009 | 0.022 ± 0.013 | 0.036 ± 0.002 | 0.120 ± 0.074 | ND | ND |
| F (AUCPR/AUCPO, %) | 25 ± 8 | 28 ± 6 | ||||
AUC, area under the concentration-vs.-time curve; CL/F, the ratio of clearance to bioavailability; Cmax, maximum plasma concentration; Cmin, concentration at the last time point collected; C12, plasma concentration at 12 h; F, relative bioavailability; MRT, mean residence time; ODMP, o-desmethyl-pimobendan; PIM, pimobendan; PO, per os; PR, per rectum; t1/2, disappearance half-life; Tmax, time to maximum concentration; V/F, the ratio of volume of distribution to bioavailability.