RT Journal Article
SR Electronic
T1 Pharmacokinetics of methylphenidate in man, rat and monkey.
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 382
OP 386
VO 226
IS 2
A1 W Wargin
A1 K Patrick
A1 C Kilts
A1 C T Gualtieri
A1 K Ellington
A1 R A Mueller
A1 G Kraemer
A1 G R Breese
YR 1983
UL http://jpet.aspetjournals.org/content/226/2/382.abstract
AB The pharmacokinetics and bioavailability of methylphenidate (MPH) and a metabolite, ritalinic acid (RA), were studied in normal adults, children with hyperactivity, monkeys and rats. Adult males received 0.15 or 0.3 mg/kg of MPH orally and MPH and RA were analyzed in plasma samples obtained at various times after treatment. Maximal MPH concentrations in plasma were found to occur 2.2 hr after administration of either dose (range: 1.0-4.0). The mean (+/-S.E.) maximal concentration in plasma for MPH was 3.5 +/- 0.4 ng/ml after 0.15 mg/kg and 7.8 +/- 0.8 ng/ml after 0.3 mg/kg. MPH clearances were high (10.1 liters/hr/kg) and variable (range: 3.6-23.2) for the 0.3 mg/kg dose. Pharmacokinetic parameters for children receiving 0.3 mg/kg were essentially the same as for adults. RA plasma levels were 50 to 100 times greater than MPH levels in normal adults. The clearance of RA is less than that of MPH. The absolute bioavailability of MPH was found to be 0.19 in the rat and 0.22 in the monkey, suggesting substantial presystemic elimination of MPH.