ABSTRACT
<p><b>OBJECTIVE</b>The present study investigates the influence of Qingkailing injection on rat liver CYP1A2 and CYP2D6 activity in vivo and in vitro, respectively.</p><p><b>METHOD</b>We employed HPLC to measure the metabolites of caffeine in the whole blood and calculated the ratio be between the metabolite and caffeine, which was used as index to evaluate the effect of Qingkailing injection on rat CYP1A2 activity in vivo; We also detected the CYP1A2 and CYP2D6 activity in microsomal reconstituted system by analysis of phenacetin metabolism and dextromethorphan metabolism with HPLC.</p><p><b>RESULT</b>The metabolism of caffeine in treated groups was (15.9 +/- 3.8)%, (14.5 +/- 1.8)%, (12.3 +/- 1.2)%, with different concentration of Qingkailing injection (0.15, 0.3, 0.6 mL x kg(-1)) compared with (16.8 +/- 5.9)% in the control group, which was no significant difference among groups. In rat liver microsomal reconstituted system, Qingkailing injection has no inhibitory effect on CYP2D6 activity while the group with high dose has inhibitory effect on rat CYP1A2.</p><p><b>CONCLUSION</b>Qingkailing injection has no inhibitory effect on rat CYP1A2 and CYP2D6 in vivo and in vitro.</p>
