Paeonol pharmacokinetics in the rat following i.m. administration.

The pharmacokinetic behavior and bioavailability of paeonol were determined after a single intramuscular (i.m.) injection of 10 mg/kg to rats. Plasma paeonol concentrations were measured by high performance liquid chromatography (HPLC). The main pharmacokinetic parameters were as follows: mean elimination half-life (t(1/2z)) 59.85 +/- 10.23 min, time to reach peak concentration (Tmax) 7.50 +/- 2.74 min, maximum concentration (Cmax) 0.71 +/- 0.13 mg/l, total body clearance (CLz) 0.24 +/- 0.03 l/min/kg, the area under concentration-time curve from 0 to 4 h (AUC(0-4h)) 39.01 +/- 5.69 mg/l x min, the area under concentration-time curve from 0 to infinity (AUC(0-infinity)) 43.06 < or = 6.10 mg/l x min. The absolute bioavailability of paeonol after i.m. administration amounted to 68.68%.