Effect of chongmyungtang,a traditional Korean polyherbal formula,on the Pharmacokinetic profiles of donepezil in rats

Chongmyungtang (cmt) is a famous korean herbal medicine for improving learning and memory,which has been reported to have anti-cholinergic and neuroprotective effects. therefore,drug-drug interactions were examined between cmt and donepezil as a first screening of combination therapy for cognitive deficits. rats received oral coadministration of donepezil with distilled water as a control or donepezil with cmt as a combination. the distilled water or cmt was co-administered at intervals within 5min after donepezil or 1.5h intervals. the plasma samples were analyzed for donepezil concentration and its pharmacokinetic parameters of tmax,cmax,auc,t1/2 and mrtinf. in the single co-administration at intervals within 5min,donepezil was detected lower in the combination than control at 0.5h and 2h post-treatment (p<0.05). in addition,the combination showed significant increases in mrtinf compared to the control (p<0.05). this suggests drug-drug interactions between donepezil and cmt in the co-administration within 5 min. however,no meaningful differences were found in the pharmacokinetic profiles of donepezil by single dosing with cmt at 1.5h intervals and even by the repeated dosing for a week at 1.5h intervals potential combination therapy of donepezil with cmt.