A Study of Paliperidone Enantiomer Disposition With Different Formulations and the Bioavailability of Immediate- and Extended-release Paliperidone

The purpose of this study is to characterize the pharmacokinetics of paliperidone in plasma and urine after intravenous (i.v.) administration of the racemate, administration of the immediate-release (IR) racemate oral solution, administration of the ER OROS tablet, and administration of the oral solutions of the individual enantiomers R078543 (+) and R078544 (-); to determine the absolute oral bioavailability of IR and ER OROS paliperidone; to document the (+) and (-) paliperidone enantiomer ratio after i.v. and oral administration (IR and ER OROS paliperidone); to document the possible interconversion between the (+) and (-) enantiomers of paliperidone after oral treatment with the separate enantiomers; to document the possible relationship between the subject's CYP2D6 phenotype and the (+) and (-) enantiomer disposition of paliperidone (CYP2D6 genotyping was used to corroborate the phenotype). In addition, the safety and tolerability of all treatments will be evaluated.