A Pharmacokinetic Study of the Relative Bioavailability of Paliperidone ER Formulations With Different Release Profiles and a Comparison to Paliperidone IR

This is a randomized, open-label, 4-way crossover, single dose study in healthy male volunteers to evaluate the pharmacokinetic profiles of paliperidone ER tablets with slow, target, and fast in vitro release rates and paliperidone IR. The study consists of a 21 day screening phase, an open-label treatment phase consisting of 4 single-dose treatment periods (IR, slow, fast, and target formulations), and an end-of-study or early withdrawal phase. A 10- to 21 day washout period (i.e., \>5 times the half-life) will separate each study drug administration (i.e., each open label treatment period). In the first period, all volunteers are given a 1-mg dose of paliperidone IR solution, administered as a single oral dose under fasted conditions (Treatment A). On Day 1 of Period 2, prior to study drug administration, all volunteers will be randomly assigned to 1 of 6 possible treatment sequences to ensure that they receive all of the following treatments, one in each period: 12-mg paliperidone ER tablet with a target in vitro release under fasted condition (Treatment B); 12-mg paliperidone ER tablet with a slow in vitro release under fasted condition (Treatment C); 12-mg paliperidone ER tablet with a fast in vitro release under fasted condition (Treatment D). In each treatment period, volunteers will enter the study center at least 10 hours before the study drug administration on Day 1 and will remain there until after collection of the 96 hour pharmacokinetic samples on Day 5 if the investigator considers that the volunteer is ready for discharge. It is expected that the differences in the in vitro release rate will not affect the relative bioavailability of paliperidone in vivo. Safety and tolerability of the different paliperidone ER formulations will be monitored throughout the study. Single oral doses of paliperidone ER 12 mg tablets with different release rates (target, fast, and slow); single oral dose of paliperidone IR 1 mg