title: The absorption of sustained-release methylphenidate formulations compared to an immediate-release formulation.
abstract: A crossover study in 18 subjects evaluated the plasma concentration-time profile of two different 20 mg sustained-release (SR) methylphenidate (MPH) tablets administered before breakfast, compared to a 10 mg immediate-release (IR) tablet administered before breakfast and again 5 h later, before lunch. Plasma MPH concentrations were determined using a sensitive and precise gas chromatography-mass spectrometry method, incorporating a deuterated internal standard. The mean peak MPH concentration was 6.4 ng ml-1 for the IR product versus 4.6 ng ml-1 and 4.8 ng ml-1 for the two SR formulations. Peak concentrations occurred at 3.3 h after dosing with the SR products, compared to 1.5 h after the first dose of the IR product. The extent of absorption for the three products, as determined from areas under the plasma concentration-time curves, were within 5 per cent of each other. There was no significant difference in rate or extent of absorption between the two SR formulations.
authors.affiliation: Department of Medicinal Chemistry, College of Pharmacy, University of Tennessee, Memphis 38163.
authors.forename: K S
authors.initials: KS
authors.lastname: Patrick
authors.forename: A B
authors.initials: AB
authors.lastname: Straughn
authors.forename: E J
authors.initials: EJ
authors.lastname: Jarvi
authors.forename: G R
authors.initials: GR
authors.lastname: Breese
authors.forename: M C
authors.initials: MC
authors.lastname: Meyer
mesh_terms: D001682:Biological Availability; D003692:Delayed-Action Preparations; D008401:Gas Chromatography-Mass Spectrometry; D006207:Half-Life; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013607:Tablets
chemical_list: D003692:Delayed-Action Preparations; D013607:Tablets; D008774:Methylphenidate