A Dose-proportionality Study of Five Tablet Strengths of ER OROS Paliperidone

This study is designed as a single-center, open-label, randomized, 5 treatment-period, crossover study in healthy male adults. The study consists of a screening phase and an open-label treatment phase during which each volunteer will receive 5 treatments of study drug in a random order and separated by a washout period of 10 to 14 days. Treatments will consist of a single oral dose of: A) 1 tablet containing 3 mg ER OROS paliperidone; B) 1 tablet containing 6 mg ER OROS paliperidone; C) 1 tablet containing 9 mg ER OROS paliperidone; D) 1 tablet containing 12 mg ER OROS paliperidone; E) 1 tablet containing 15 mg ER OROS paliperidone. All treatments will be administered after an overnight fast. Volunteers are to remain in bed for 4 hours after dosing and are strongly advised to remain in bed for up to 36 hours. Five different ER OROS paliperidone tablet strengths (3, 6, 9, 12, and 15 mg) will be developed with the intent to market. Since ER OROS paliperidone is an extended release formulation, this study is designed to show dose-proportional pharmacokinetics of all these dose strengths. Safety and tolerability will be monitored throughout the study. Treatments will consist of a single oral dose of: A) 1 tablet containing 3 mg ER OROS paliperidone; B) 1 tablet containing 6 mg ER OROS paliperidone; C) 1 tablet containing 9 mg ER OROS paliperidone; D) 1 tablet containing 12 mg ER OROS paliperidone; E) 1 tablet containing 15 mg ER OROS paliperidone