Study on Pharmacokinetics of the Sustained-release Tablets and Common Tablets of Melatonin in Beagle Dogs in Vivo

OBJECTIVE:To compare pharmacokinetic parameters of the common tablets and sustained-release melatonin tablets in beagle dogs in vivo.METHODS:The blood concentration of melatonin of6Beagle dogs was determined by HPLC and the pharmacokinetic parameters were calculated with3p97software after administered random crossover with single dose of sustained-release melatonin tablets6mg or the common tablets3mg.RESULTS:The concentration-time curves of both the common tablets and sustained-release melatonin tablets were in conformity with two-compartment model,C max of common tablets and sustained-release tablets were(11.27±3.77)ng/ml and(8.31±5.11)ng/ml respectively,t max of which were(0.50±0.18)h and(1.00±0.37)h respectively,t 1/2ke of which were(1.21±0.52)h and(3.27±0.89)h,AUC 0～t of which were(25.23±7.71)(ng·h)/ml and(38.03±16.45)(ng·h)/ml respectively.CONCLUSION:Compared with the common tablets,the sustained-release tablets showed slower absorption,longer peak time,lower peak concentration,slower elimination and longer duration.