Study on the Pharmacokinetics Drug-drug Interaction of Danmo Capsules with Prednisone in Rats

The Danmo Capsule (DMC) is a widely used patent Chinese botanic drug, prepared with the extract of Radix salviae miltiorrhizae and Ecliptae prostratae. Drug-drug interaction of DMC and prednisone was investigated in rats via in vivo pharmacokinetic studies. After pretreatment with DMC at daily dosages of 0.432 g kg(-1) for 14 consecutive days, there were significant decrease in the peak plasma concentration (C-max) of prednisone (from 174.6 +/- 32.9 ng mL(-1) to 68.2 +/- 35.2 ng mL(-1), p<0.01) and in the area under the plasma concentration-time curve (AUC(0-2.5h)) of prednisone (from 225.9 +/- 55.8 h.ng mL(-1) to 128.8 +/- 37.5 h.ng mL(-1), p<0.05), respectively. In contrast to prednisone, the C-max of prednisolone was significantly increased from 155.9 +/- 40.4 ng mL(-1) to 333.20 +/- 95.8 ng mL(-1) (p<0.05) and the AUC(0-8h) of prednisolone was significantly increased from 467.5 +/- 35.3 h.ng mL(-1) to 757.3 +/- 105.4 h.ng mL(-1) (p<0.01), respectively. However, no statistically significant differences for the elimination half-life (t(1/2)) and Mean Residence Time (MRT) of prednisone and prednisolone were detected. In conclusion, the increased C-max and AUC of prednisolone showed co-administration with DMC significantly increased exposure of prednisolone.