Introduction. The importance of generic drugs is the possibility of reduced costs in the national healthsystem without sacrificing quality of service and the efficacy and safety of treatments.However, bioequivalence studies must show that the pharmacokinetic profiles of the test product andreference product are similar and interchangeable. Montelukast sodium is indicated for the prophylaxisand chronic treatment of asthma in adults and pediatric patients 12 months of age or older. It is generallywell tolerated, although adverse reactions are more frequent in patients treated with the drug than inthose treated with placebo.Objectives. To compare the bioavailability of Amisped® (5 mg montelukast chewable tablets)manufactured by Sanofi-Aventis and 5 mg chewable tablet montelukast (Singulair®) developed by Merck.Materials and methods. The magnitude and rate of absorption of montelukast was compared in 18healthy volunteers using a randomized complete crossover design. The bioassay was performed byhigh performance liquid chromatography.Results.Results are indicated for the generic and innovator, respectively: Tmax (h) 2.17±0.73, 2.28±0.88;Cmax (ng/mL) 607.4±122.9, 627.7±134.2; AUC0-t (ng*h/ml) 3,316±861, 3,545±1,070; AUC0-∞ (ng*h/ml) 3,450±904, 3,722±1121; Ke (1/h) 0.25±0.05, 0.23±0.04 in the confidence range of 0.99-1.00 for lnCmaxand 0.94-1.06 for lnAUC0-∞.Conclusions. The formula tested in Amisped® from Sanofi-Aventis is bioequivalent to the referenceformulation of Merck Singulair®.doi: http://dx.doi.org/10.7705/biomedica.v32i3.708