A Phase 1 Bioavailability Study of Topiramate Oral Liquid Formulation Compared to the Marketed Sprinkle Capsule Formulation in Healthy Adults

The primary purpose of this study is to estimate the bioavailability of the oral liquid formulation of topiramate relative to the commercially available oral sprinkle capsule formulation in healthy patients. If appropriate, bioequivalence between the oral liquid formulation and the sprinkle capsule formulation will be assessed.

This is a randomized, open-label, 2-way crossover, single-center, relative bioavailability study in healthy adult men and women. The study was conducted in 3 phases: a pretreatment phase (Days -14 to -1), a 25-day open-label treatment phase, and a 7-day follow-up phase. Patients will enter the screening phase no more than 14 days prior to receiving study treatment. During the screening period, patients' eligibility will be assessed, and physical examinations and other safety evaluations will be performed. Eligible patients will be randomized at baseline (Day -1) to receive the topiramate oral liquid and sprinkle capsule formulations according to 1 of 2 treatment sequences (see Section 5, Randomization and Blinding). There will be a 3 week washout period between treatments. Initially, approximately 40 patients will be enrolled in the study, in order for at least 32 patients to complete all PK assessments. Patient will be confined to the study site on the evenings of Days -1 and 20. Following a 10-hour overnight fast, patients will receive topiramate as a single 100-mg dose of the oral liquid formulation and the oral sprinkle capsule formulation according to the sequence specified by the randomization schedule at approximately 8 a.m. on Days 1 and 21. Serial blood samples will be collected for estimation of plasma topiramate concentrations at scheduled times from predose through 96 hours postdose. Patients will be discharged from the study site on Days 3 and 23 after collection of the 48 hour postdose blood sample. Patients will arrive at the study site 2 hours prior to PK sample collection to obtain the 60 hour (Days 3 and 23), 76 hour (Days 4 and 24), and 96 hour (Days 5 and 25) postdose samples. Patients will complete the study on Day 25 and receive a follow-up phone call on Day 32 for an adverse event assessment. Safety and tolerability will be assessed throughout the study. Patients will be randomly assigned to receive both oral treatments: A then B, or B then A. Treatment A: Topiramate 100 mg as 20 mL of a 5 mg/mL liquid formulation and Treatment B: Topiramate 100 mg as 4 X 25-mg sprinkle capsule formulation There is a 3 week wash-out period between treatments