Phase I pharmakinetics of tramadol hydrochloride paracetamol capsules in Chinese healthy volunteers

OBJECTIVE To investigate the pharmacokinetics of tramadol hydrochloride paracetamol capsules after oral administration in Chinese healthy volunteers.METHODS 10 heathy volunteers(5 men and 5 women) were given with 2 capsules.The plasma concentrations of tramadol were determined by HPLC-FLD and paracetamol by HPLC-UV.RESULTS Pharmacokinetics profiles were fitted to a one compartment model calculated using PKS software.Pharmacokinetics parameters were as followings: paracetamol Cmax was(9.5±2.4)mg·L-1,tmax was(0.68±0.24)h,t1/2 was(6.0±1.6)h,AUC0-24 was(30.9±8.5)mg·L-1·h,AUC0-∞ was(32.1±8.7)mg· L-1·h;tramadol Cmax was(247.0±45.1)μg·L-1,tmax was(1.6±0.8)h,t1/2 was(5.5±1.4)h,AUC0-24 was(1 712.6±556.3)μg·L-1·h,AUC0-∞was(1 872.8±623.3)μg·L-1·h.CONCLUSION The pharmacokinetics parameters of tramadol hydrochloride paracetamol capsules in Chinese healthy volunteers show no difference to those reported in the literature