Abstract

This study was performed to assess the bioequivalence of fexofenadine 120 mg+montelukast 10 mg fixed dose combination (Allegra™ M) with separate formulations of fexofenadine (Allegra™) and montelukast (Singulair^®) administered concurrently at the same dose levels. This was a randomized, open-label, two-treatment, two-period, two-sequence, single-dose, crossover study in 60 healthy adult men under fasting conditions. Initially, 30 subjects received a single oral dose of fexofenadine Allegra M combination tablet, while the remaining 30 subjects received concurrent single oral doses of fexofenadine 120 mg and montelukast 10 mg tablets. After a 10 d washout period, subjects crossed over to the alternate treatment. Plasma concentrations of fexofenadine and montelukast were determined using a liquid chromatography coupled to tandem mass spectrometry single assay method; the lower limit of quantitation for both the analytes was 2.00 ng/ml. Of the 60 subjects included, 57 completed both periods of the study. The 90% confidence interval for the geometric mean ratio of maximum concentration, area under the concentration-time curve from 0 to interval t, and area under the concentration-time curve from 0 to infinity were within the range of 80-125% for both fexofenadine and montelukast in the test and reference products, indicating bioequivalence between the fixed dose combination and individual components. Six subjects (three in each group reference and test) experienced six adverse events. The most frequently reported adverse event was vomiting, reported by four subjects. All the adverse events were reported as possibly related to the test product, and no serious adverse events were reported. Allegra M fixed dose combination was bioequivalent to the individual components of the same strength administered concurrently.