The Pharmacokinetic Exposure to Fexofenadine is Volume‐Dependently Reduced in Healthy Subjects Following Oral Administration With Apple Juice

Pharmacokinetic exposures to fexofenadine (FEX) are reduced by apple juice (AJ); however, the relationship between the AJ volume and the degree of AJ‐FEX interaction has not been understood. In this crossover study, 10 healthy subjects received single doses of FEX 60 mg with different volumes (150, 300, and 600 mL) of AJ or water (control). To identify an AJ volume lacking clinically meaningful interaction, we tested a hypothesis that the 90% confidence interval (CI) for geometric mean ratio (GMR) of FEX AUC(AJ)/AUC(water) is contained within a biocomparability bound of 0.5–2.0, with at least one tested volume of AJ. GMR (90% CI) of AUC(AJ 150mL)/AUC(water), AUC(AJ 300mL)/AUC(water), and AUC(AJ 600mL)/AUC(water) were 0.903 (0.752–1.085), 0.593 (0.494–0.712), and 0.385 (0.321–0.462), respectively. While a moderate to large AJ‐FEX interaction is caused by a larger volumes of AJ (e.g., 300 to 600 mL), the effect of a small volume (e.g., 150 mL) appears to be not meaningful.