Studies of the pharmacokinetics of paeoniflorin in two Jing-Zhi-Guan-Xin formulations after oral administration to beagle dogs.

Paeoniflorin is the principal bioactive component of Paeoniae Radix. The traditional chinese medicine compound recipe (TCMCR) tablets of Jing-Zhi-Guan-Xin (JZGX), which is composed of Radix Salviae Miltiorrhizae, Radix Paeoniae Rubrae, Rhizoma Chuan-xiong, Flos Carthami and Lignum Dalbergiae Odorafera, have been widely used in China and Japan. The plasma concentrations of paeoniflorin in beagle dogs after oral administration of two Jing-Zhi-Guan-Xin formulations (the dose used in the two formulations were both 200 mg paeoniflorin) were measured using a simple and rapid HPLC method. The mean terminal half-lives (t1/2) of JZGX tablet and JZGX elementary osmotic pump tablet (EOPT) formulations of paeoniflorin were 147.52 +/- 28.98 and 276.60 +/- 24.24 min, the maximum plasma concentrations (Cmax) of paeoniflorin were 210.49 +/- 23.89 and 94.36 +/- 14.01 ng/ml, times to reach maximum concentrations (tmax) were 130.00 +/- 30.98 and 280.00 +/- 48.99 min, the area under the plasma concentration-time curves (AUC0-infinity) were 43066.50 +/- 10119.51 and 42266.87 +/- 2654.90 ng min/ml, the mean residence times (MRT) were 212.87 +/- 41.82 and 399.14 +/- 34.98 min, respectively, and the relative bioavailability (Fr) of JZGX EOPT compared with JZGX tablet was 101.8 +/- 18.8%. These results, compared with the pharmacokinetic parameters of paeoniflorin after oral administration of Paeoniae Radix extract alone, indicated that the absorption of paeoniflorin after oral administration of the two JZGX formulations was significantly greater than that after oral administration of Paeoniae Radix extract alone.