The official study title is as follows: A Randomized, Open-label, Single-dose, Three-way Crossover Study to Determine the Relative Pharmacokinetic Profile of Oral Doses of CONCERTA Tablets, Ritalin-SR Tablets and Novo-Methylphenidate ER-C Tablets Under Fasted Condition in Healthy Subjects. Methylphenidate is indicated for the treatment of attention deficient hyperactivity disorder in adults, adolescents and children. Each volunteer will receive one 54-mg CONCERTA tablet(once), one 54-mg Novo-Methylphenidate ER-C tablet (once) and three 20mg Ritalin-SR tablets (once) at specified time points in the study. Tablets will be administered as a single oral dose under fasted (minimum 10 hour fast) conditions. Study drug will be administered orally with 240 mL of room temperature noncarbonated water.