Bioequivalence Study Comparing 2 Formulations for 4 mg Risperidone Tablet.

This is a single-center, open, randomized, 2-way crossover bioequivalence study in 40 subjects with schizophrenia or schizoaffective disorder. The study will consist of 2 treatment periods, 5 days per period. The subjects will receive a single 4 mg RISPERDAL conventional tablet in period 1 and a single 4 mg orally-disintegrating tablet in period 2; or the orally disintegrating tablet in period 1 and conventional tablet in period 2. A washout period of at least 10 days between Day 1 of Period 1 and Day 1 of Period 2 will separate the 2 treatments. In both treatment periods plasma concentrations of the drug will be measured. Serial blood collections will be made beginning at 0 hour (immediately before study drug administration) and continuing up to 96 hours after study drug administration in each period. Safety will be evaluated throughout the study using physical examinations, electrocardiogram recordings (ECG), clinical laboratory testing (hematology, serum chemistry, urinalysis), vital signs measurements, pregnancy testing, drug screening, and monitoring of adverse events. The study will be approximately 6 weeks long (including the screening period). Subjects will enter the study facility 3 days before the first administration of study medication on Day 1 of the first period. They will remain at the facility until all study-related procedures are completed on Day 5 of the second study period, a period of approximately 18 days. 4 mg risperidone (either conventional tablet or orally-disintegrating tablet), single dose, oral intake