Abstract
Objective: To determine the relative bioavailability of two nimesulide preparations commercially available in Italy [the original product Aulin® (test preparation) and a generic product Nimesulide Dorom (reference preparation)] following single oral administration to healthy volunteers, since in vitro investigation has shown that the dissolution of nimesulide from Aulin® is faster and more complete than from the generic product.
Design: Randomised, two-way, cross-over study.
Patients and Participants: 18 healthy male volunteers.
Methods: Blood samples were withdrawn up to 24 hours after administration of the two preparations, each containing 100mg of nimesulide, and the plasma concentrations of nimesulide and its main metabolite 4′-hydroxy-nimesulide were quantified using a validated high performance liquid chromatography analytical method with ultraviolet detection.
Results: For the area under the curve calculated from time zero to infinity (AUC0-∞), arithmetic mean values for nimesulide were 19.93 (test preparation) and 9.32 (reference preparation) mg·h/L. The corresponding values for the metabolite 4′-hydroxy-nimesulide were 11.95 and 5.59 mg·h/L, respectively. The mean peak nimesulide plasma concentrations (Cmax) [value for the metabolite in parentheses] were 4.67 (1.63) mg/L for the test preparation and 1.60 (0.65) mg/L for the reference preparation. In addition, for nimesulide the ratio Cmax/AUC0-∞ was calculated. The values obtained were 0.25h−1 (test) and 0.18h−1 (reference). Statistical comparisons of all three parameters (analysis of variance and confidence intervals) after logarithmic transformation showed significant differences and bioinequivalence between the test and reference preparations.
Conclusions: According to the results obtained in this study, the generic product Nimesulide Dorom cannot be regarded as comparable to the original product Aulin®, and consequently the two preparations cannot be considered interchangeable products according to the World Health Organization definition of generics.