Pharmacokinetics of paracetamol and caffeine in paracetamol,caffeine,atificial cow-bezoar and chlorphenamine maleate capsules in healthy volunteers

AIM To investigate the pharmacokinetics of paracetamol and caffeine in paracetamol,caffeine,atifi- cial cow-bezoar and chlorphenamine maleate capsules.METHODS A sensitive and rapid HPLC method was developed to determine paracetamol and caffeine concentration simultaneously in human plasma.Data of plasma level-time were dis- posed with 3P97 software.RESULTS The main pharmacokinetic parameters of paracetamol were as follows:t_(max)(1.03±0.76)h,ρ_(max)(12.00±3.10) mg·L~(-1),t_(1/2)(4.33±1.18)h,AUC_(0→t)(52.51±16.81) mg·h·L~(-1),AUC_(0→∞)(54.34±17.72)mg·h·L~(-1),respectively.For caffeine,the main pharmacokinetic parameters were as follows:t_(max)(0.89±0.50) h,ρ_(max)(1.290±0.379)rng·L~(-1),t_(1/2)(5.37±2.15)h,AUC_(0→t)(7.19±3.03)mg·h·L~(-1),AUC_(0→∞)(8.26±3.69)mg·h·L~(-1),respectively.CONCLUSION The plasma concentration-time curves of paracetamol and caffeine appear to fit two and one compartment models,respectively.