In vivo pharmacokinetics of major bioactive components from Tanreqing Injection in rats / 中草药

ABSTRACT

Objective: To investigate the in vivo pharmacokinetic characteristics of Tanreqing Injection in rats. Methods: Using baicalin (BC), ursodeoxycholic acid (UDCA), and chenodeoxycholic acid (CDCA) in Tanreqing Injection as biomarkers to characterize the in vivo pharmacokinetics. Rats were received an iv administration of Tanreqing Injection in single dose (1.25, 2.5, and 5.0 mL/kg) or multiple doses (5.0 mL/kg), and the blood concentration of BC was determined using LC-UV method, and the concentration of UDCA and CDCA was determined using LC-MS method. The pharmacokinetic parameters were analyzed by WinNonlin 6.3 software. Results: After a single iv administration of Tanreqing Injection (2.5 mL/kg) to rats, the values of t1/2 for BC, UDCA, and CDCA were (48.19 ± 12.74), (56.19 ± 33.33), and (109.96 ± 58.39) min, and AUC0-6h were (1718.02 ± 656.49), (1150.83 ± 371.53), and (541.52 ± 403.69) μg·min/mL. Within the tested dose range from 1.25 to 5.0 mL/kg, the values of t1/2 for the three major bioactive components were not affected by the dose, and AUC0-6h for BC and UDCA showed a good linearity to the dosage (r > 0.99), but AUC0-6h of CDCA was positively correlated with the dosage. After multiple iv administration of Tanreqing Injection (5.0 mL/kg), the values of AUC0-6h for BC, UDCA, and CDCA were (2872.37 ± 476.45), (3339.63 ± 939.94), and (1241.29 ± 408.38) μg·min/mL, and the accumulation index values were 83.3%, 118.5%, and 168.0%, respectively. Conclusion The elimination of BC and UDCA after single iv administration (1.25-5.0 mL/kg) is linear, and CDCA is probably linear after the administration. There is no significant accumulation in blood concentration for BC and UDCA, but CDCA has a tendency of accumulation after the multiple injection.