There are two specific aims of this study. The first is to document the pharmacokinetics of dopamine transporter (DAT) receptor occupancy of repeated administration of orally administered, therapeutic doses of a short immediate release-methylphenidate hydrochloride (IR-MPH) and a long-acting formulation of MPH (OROS-MPH) using positron emission tomography (PET) scanning with C-11 altropane as the ligand. The investigators hypothesize that central nervous system (CNS) DAT occupancy of the OROS-MPH to IR-MPH sequence will be greater than that of IR-MPH to OROS-MPH sequence at 5 hours after the initial administration and that the CNS DAT occupancy of the other two formulations will be intermediate. The second aim of this study is to assess whether the abuse liability potential of delayed, repeated administrations of different formulations of MPH is moderated by the oral delivery system in which a delivery system with slower onset may be safer than one with more rapid early release.
ROS-MPH's pharmacokinetic profile uses an increasing delivery of MPH over the day (ascending pharmacokinetic curve). It was designed to replace IR-MPH TID treatment. The main target of MPH in the brain is the dopamine transporter (DAT). We have an exquisitely sensitive methodology to measure DAT occupancy using C-11 Altropane and Positron Emission Tomography (PET). The time course of decay of the C-11 Altropane permits repeated imaging, thus allowing documentation of the pharmacokinetics of DAT receptor occupancy. We will test all combinations of initial administration and then delayed (repeated) administration of the two formulations: IR-MPH to IR-MPH; IR-MPH to OROS-MPH; OROS-MPH to IR-MPH; and OROS-MPH to OROS-MPH.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Masking
NONE
Enrollment
20
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.
Massachusetts General Hospital
Boston, Massachusetts, United States
The DAT receptor occupancy of OROS MPH and MPH IR using PET scanning with C-11 altropane. Objective measures also provided by d and l ritalinic acid and methylphenidate levels at pre-dose, hour 4, 5 and 6.
The first visit will consist of a baseline PET scan during which no medication will be administered. For the next four study visits, 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. The study visits may be scheduled five to 30 days apart, but each subject must complete the five visits within a ten-week period.
Time frame: Eligible subjects will be asked to return to the study center for five study visits.
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