Research article summary (published 30 Aug 2008):

A pharmacokinetic study of two modified-release methylphenidate formulations under different food conditions in healthy volunteers.

Full Abstract

OBJECTIVES: Primary objective was to investigate bioequivalence of Ritalin LA(R); 40 mg compared to Medikinet retard 40 mg in healthy male volunteers under fasted and fed conditions. Secondary objectives included assessment of tolerability and determination of further pharmacokinetic parameters. The difference between the kinetic profiles of Ritalin LA(R) and Medikinet retard with respect to breakfast intake was additionally explored. METHODS: 28 subjects were randomized in this open-label, four-treatment, cross-over-design study. Pharmacokinetic evaluations included AUC(0-inf), Cmax, tmax, elimination half life (t1/2) and mean residence time MRT(0-inf)). The relative bioavailability of Ritalin LA(R) and Medikinet retard and the food effect were assessed using a 90% confidence interval (CI) based on the lower and upper endpoints of the CI for the ratios of the geometric means being within the 80 - 125% equivalence criterion. RESULTS: 25 volunteers completed all treatment arms. Frequency of adverse events were comparable for all treatments. Under fasted condition Ritalin LA(R) showed a consistent bimodal concentration time profile with two tmax peaks. Medikinet retard showed a steady absorption with a single tmax peak. The point estimators for AUC(0-inf) and Cmax were found to be 99.7% and 85.9%, respectively. Under fed condition both Ritalin LA(R) and Medikinet retard showed a bimodal concentration time profile with two tmax peaks. The point estimators for AUC(0-inf) and Cmax were estimated as 89.8% and 68.6%, respectively. CONCLUSIONS: Both methylphenidate formulations were safe and well tolerated. Ritalin LA and Medikinet retard were bioequivalent in fasted state but not in fed state. Only Ritalin LA had a biphasic kinetic profile under both fasted and fed conditions. This difference in the kinetic profiles might be of clinical relevance and might offer a potential advantage of Ritalin LA.

Author information

Author/s: Haessler, F (F); Tracik, F (F); Dietrich, H (H); Stammer, H (H); Klatt, J (J);

Affiliation: Clinic for Child Psychiatry, Neurology, Psychosomatics and Psychotherapy, University Hospital Rostock, Germany.

Journal and publication information

Publication Type: Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't

Journal: International journal of clinical pharmacology and therapeutics (Int J Clin Pharmacol Ther), published in Germany. (Language: eng)

Reference: 2008-Sep; vol 46 (issue 9) : pp 466-76

Dates: Created 2008/09/16; Completed 2008/12/01;

PMID: 18793577, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MeSH Headings (categories) shown below.

Administration, Oral Adolescent Adult Area Under Curve Biological Availability Central Nervous System Stimulants - administration & dosage; adverse effects; pharmacokinetics Cross-Over Studies

Delayed-Action Preparations Food-Drug Interactions Half-Life Humans Male Methylphenidate - administration & dosage; adverse effects; pharmacokinetics Therapeutic Equivalency

Note: Bold headings indicate primary MeSH headings or qualifiers.

Associated Chemicals: Central Nervous System Stimulants (0) ; Delayed-Action Preparations (0) ; Methylphenidate (113-45-1)

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