A randomized, open-label, crossover study evaluating bioequivalence of two N-acetylcysteine 2% oral solution formulations in healthy subjects

Objective: N-acetylcysteine is a mucolytic agent used to treat bronchopulmonary diseases associated with airway mucus hypersecretion. The bioequivalence of a new oral N-acetylcysteine 2% formulation was evaluated relative to an appropriate reference product. Materials and methods: This open-label, randomized, crossover study assessed the bioequivalence of a new N-acetylcysteine 2% oral solution compared to an approved reference N-acetylcysteine 2% oral solution in healthy subjects in terms of pharmacokinetics, including area under the plasma concentration vs. time curve of N-acetylcysteine plasma concentrations from time 0 to the last measurable sampling time point and the maximum postdose concentration. Bioequivalence was concluded if the 90% confidence intervals for the ratio of the geometric means of the two pharmacokinetic parameters with baseline correction were entirely within the range of 80 -125%. Results: 46 participants were randomized. The ratios of the geometric means for the test vs. reference treatment, with baseline correction, were 1.0961 (90% confidence interval: 1.0228, 1.1746) for area under the plasma concentration curve of test N-acetylcysteine plasma concentrations and 1.0938 (90% confidence interval: 1.0142, 1.1796) for maximum postdose concentration; both were within the predefined range to demonstrate biocquivalence. Most treatment-emergent adverse events were mild or moderate and not considered study drug related. Conclusion: The new N-acetylcysteine 2% oral solution was found to be bioequivalent to the marketed reference formulation. Treatments were generally safe and well tolerated.