Pharmacokinetics and bioequivalence of paracetamol in compound tablets of paracetamol,pseudoephedrine and dextromethorphan or paracetamol,pseudoephedrine,diphenhydramine and dextromethorphan in healthy volunteers

AIM:To study the pharmacokinetics and bioequivalence of paracetamol in the compound tablets of paracetamol,pseudoephedrine and dextromethorphan or paracetamol,pseudoephedrine,diphen- hydramine and dextromethorphan in healthy volunteers.METHODS:In a randomized crossover study,20 healthy male volunteers were given orally individual administration of two compound tablets containing paracetamol,pseudoephedrine and dextromethorphan or paracetamol,pseudoephedrine,diphenhydramine and dextromethorphan.Paracetamol in plasma was determined by a HPLC method.RESULTS:As regard to the compound tablets of paracetamol,pseudoephedrine and dextromethorphan,the main pharmacokinetic parameters for paracetamol of test and reference preparations were c_(max) (7.6±s 2.1),(6.6±1.2) mg·L~(-1);t_(max) (0.9±0.6),(1.1±0.6) h;AUC_(0-16) (29±4),(28±5) mg·h·L~(-1),respectively.The relative bioavailability of paracetamol in test preparation was (103±8)%.To the compound tablets of paracetamol,pseudoephedrine, diphenhydramine and dextromethorphan,the main pharmacokinetic parameters for paracetamol of test and reference preparations were c_(max) (6.0±1.0),(6.2±1.2) mg·L~(-1);t_(max) (1.5±0.7),(1.3±0.7) h;AUC_(0-16) (29±6),(29±7) mg·h·L~(-1),respectively.The relative bioavailability of paracetamol was (99±10)%. CONCLUSION:For detection of paracetamol,the test and reference preparations are bioequivalent.