Randomized, open-label, single-dose, crossover, relative bioavailability study in healthy adults, comparing the pharmacokinetics of rabeprazole granules administered using soft food or infant formula as dosing vehicle versus suspension.

BACKGROUND: A sprinkle capsule formulation containing enteric-coated, delayed-release rabeprazole granules is being developed for the treatment of children with gastrointestinal reflux disease. The granules are designed to be mixed with vehicles that facilitate delivery to children, who may be unable to swallow solid formulations. OBJECTIVE: The primary objective of this study-conducted on the sponsor's initiative-was to compare the bioavailability of rabeprazole granules when mixed with various dosing vehicles (small amount of soft food or infant formula) with that of a rabeprazole suspension with inactive vehicle granules (reference), to determine which dosing vehicle can be used to deliver rabeprazole in children. Tolerability was also assessed. METHODS: This single-center, single-dose, randomized, open-label, 5-period crossover study was conducted in 35 healthy adult subjects. In a randomized sequence, fasting subjects received a single dose of 10-mg rabeprazole granules per treatment period, mixed with small amounts of 1 of 5 dosing vehicles (a strawberry-flavored suspension of rabeprazole granules with inactive vehicle granules reconstituted with water, yogurt [1 tablespoon], applesauce [1 tablespoon], or infant formula [5 mL], or a suspension of rabeprazole granules with inactive vehicle tablet reconstituted with water). Full plasma pharmacokinetic (PK) profiles of rabeprazole and its thioether metabolite were collected; concentrations were estimated via LC-MS/MS. PK properties were estimated using noncompartmental methods; 90% CIs around least squares mean test-to-reference ratios were calculated for C(max) and AUC values. All treatment-emergent adverse events (TEAEs) were recorded and assessed for severity (mild, moderate, or severe) and relationship to study drug. RESULTS: A total of 35 subjects were enrolled (mean age, 38 years; 54.3% female; 100% white; mean weight, 71.4 kg). Thirty-four subjects completed the study. Rabeprazole and rabeprazole thioether plasma PK properties were comparable between all of the dosing vehicles tested. Median T(max) was 2.5 to 3.0 hours, and mean elimination half-life was 1.27 to 1.43 hours. The 90%CIs for the least squares mean ratios for rabeprazole and rabeprazole thioether exposure were within the 80% to 125% bioequivalence limits for all relevant comparisons. All TEAEs were of mild or moderate intensity, with headache being the most commonly reported; 21 subjects (60%) experienced TEAEs during the study. No deaths or serious AEs were reported during the study; 1 subject experienced a TEAE (urinary tract infection) that led to the discontinuation of treatment. CONCLUSION: In these healthy adult subjects, the bioavailability of rabeprazole granules was comparable between all of the dosing vehicles tested, and rabeprazole was well tolerated. Soft food suitable for young children or infant formula may be appropriate for use as dosing vehicles for rabeprazole granules.