title: Stereoselective disposition of methylphenidate in children with attention-deficit disorder.
abstract: Six boys with attention-deficit disorder were given single doses (5 or 10 mg) of dl-threo-methylphenidate (Ritalin, Ciba-Geigy, Basel, Switzerland). Plasma samples through 8 hr were analyzed by capillary column gas chromatography with electron capture detection. Enantiomers were separated and measured as heptafluorobutyryl-1-prolyl derivatives. The method was sensitive to 0.1 ng of enantiomer per ml of plasma. The plasma levels of d-methylphenidate were at least 5-fold greater than those of the l-enantiomer in the profiles of all six children. Mean areas under the plasma level-time curves were 24.48 +/- 7.62 ng/hr/ml for d-methylphenidate and 3.77 +/- 1.04 ng/hr/ml for l-methylphenidate. There was appreciable intersubject variation in plasma level maxima and times to maximal plasma levels of each enantiomer.
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood*; D002648:Child; D002849:Chromatography, Gas; D006801:Humans; D007700:Kinetics; D008297:Male; D008774:Methylphenidate / Q000097:blood*; D013237:Stereoisomerism
chemical_list: D008774:Methylphenidate