Bioequivalence of 2 Pediatric Formulations of Fexofenadine Hydrochloride Oral Suspension

Abstract

Fexofenadine hydrochloride (HCl) is a second-generation, nonsedating, histamine H1-receptor antagonist used to manage seasonal allergic rhinitis and chronic idiopathic urticaria. A new oral pediatric suspension of fexofenadine HCl has been developed, with the preservative potassium sorbate replacing parabens. The objective of this phase 1 single-center, open-label, randomized, 2-treatment, full-replicated, 4-period, 2-sequence crossover study in healthy adult volunteers was to assess the bioequivalence of 30 mg of the new oral suspension of fexofenadine HCl (test) versus 30 mg of the marketed pediatric oral suspension of fexofenadine HCl (reference). The replicate design was based on the high intra-individual variability of fexofenadine (>30% on Cmax). The study comprised 68 randomized and treated volunteers. Plasma concentrations of fexofenadine were similar following the administration of a single dose of each formulation. Cmax, AUClast, AUC, median tmax, and mean t1/2z were similar between administrations of the same fexofenadine formulation and between formulations. A high intra-individual variability was confirmed with both formulations. Bioequivalence of the test and reference fexofenadine HCl formulations was demonstrated as the 90% confidence intervals of the geometric least squares mean ratio for Cmax, AUClast, and AUC of fexofenadine were all within the bioequivalence range of 0.80-1.25. There were no serious adverse events (AEs) or study discontinuations due to treatment-emergent AEs with either fexofenadine HCl formulation. The new paraben-free fexofenadine HCl 30-mg oral suspension and marketed fexofenadine HCl 30-mg pediatric oral suspension are bioequivalent under fasting conditions, with no safety concerns and a safety profile consistent with the known profile of fexofenadine.