The purpose of this study was to evaluate the relative bioavailability and safety of a multilayer extended-release bead methylphenidate ( MPH ) hydrochloride @mg ( MPH-MLR ) capsule or sprinkles ( @ % immediate-release -LSB- IR -RSB- ) versus MPH hydrochloride IR ( Ritalin ( ) ) tablets , and to develop a pharmacokinetic ( PK ) model simulating MPH concentration-time data for different MPH-MLR dosage strengths .