Study on pharmacokinetics and relative bioavailability of nimesulide suppositories

Objective To study the relative bioavailability and bioequivalence of nimesulide suppositories in New Zealand rabbits.Methods A rapid and sensitive HPLC method was applied for the determination of the drug levels in plasma.In a randomized two way crossover design, the drugs were administrated by rectal and gastric,respectively in 50 mg·kg -1 single dose,to 5 male New Zealand rabbits.The parameters were estimated by two compartment model with a statistic analysis of PEMs.Results The T max ,C max ,AUC 0 inf ,t 1/2α ,t 1/2β ,MRT,lag time of nimesulide common tablets and suppositories were(6 96±1 69)h and (2 03±1 07)h,(65 51±28 09)mg·L -1 and (65 99±12 13) mg·L -1 , (519 34±151 05) mg·h·L -1 and (440 12±72 89) mg·h·L -1 ,0 63±0 13)h and(2 29±0 82)h,(1 72±0 95)h and(1 76±0 21)h, 9 00±1 16)h and(6 24±0 62)h,(5 42±1 63)h and(0 07±0 09)h,respectively.The mean relative bioavailability of the nimesulide suppositories vs common tablets was 84 75%.Conclution The results suggested that the two formulations were not bioequivalent and the nimesulide suppositories realeased more quickly than common tablets did.