Study Examining Repeat Dosing of OROS® Methylphenidate (CONCERTA®) and Immediate Release Methylphenidate in Healthy Adults

Subjects will be administered a first dose of one of the study treatments at hour 0 and then a second dose of one of the study treatments at hour 4 at each of the four treatment days in a crossover fashion, so that each subject will have received doses of each combination of treatments during the study. Each dose of OROS MPH will be 36 mg which will be supplied as one 36 mg capsules. Study treatments will be administered with water following an overnight fast of at least 8 hours.

Subjects will be administered a first dose of one of the study treatments at hour 0 and then a second dose of one of the study treatments at hour 4 at each of the four treatment days in a crossover fashion, so that each subject will have received doses of each combination of treatments during the study. Each dose of IR MPH will be 20 mg which will be supplied as one 20 mg capsule. Study treatments will be administered with water following an overnight fast of at least 8 hours.