title: Chronic administration does not alter the pharmacokinetic profile of L-dopa in the rat.
abstract: Chronic administration of L-dopa (200 mg kg-1 day-1 for 12 months) plus carbidopa (25 mg kg-1 day-1) or carbidopa (25 mg kg-1 day-1) alone did not alter the t1/2, AUC0-infinity k10, k12, k21, CLp or Vdss of L-dopa following intra-aortic (i.a.) administration (50 mg kg-1) alone or after carbidopa (25 mg kg-1, i.p.) pretreatment, or the t1/2, AUC0-infinity, tmax or the bioavailability (F) of L-dopa (50 mg kg-1) administered orally, alone or after acute pretreatment with carbidopa (25 mg kg-1 i.p.). The peripheral metabolism of L-dopa was unaltered by chronic administration of L-dopa plus carbidopa or carbidopa alone as measured by unaltered AUC0-360 min for 3-O-methyldopa, dopamine, DOPAC or homovanillic acid in the plasma of rats following acute administration of L-dopa (50 mg kg-1, p.o. or i.a.) alone or following pretreatment with carbidopa, and unaltered hepatic dopa decarboxylase activity.
authors.affiliation: Parkinson's Disease Society Experimental Research Laboratories, King's College, London, UK.
authors.forename: S
authors.initials: S
authors.lastname: Rose
authors.forename: P
authors.initials: P
authors.lastname: Jenner
authors.forename: C D
authors.initials: CD
authors.lastname: Marsden
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002230:Carbidopa / Q000494:pharmacology; D004296:Dopa Decarboxylase / Q000187:drug effects / Q000378:metabolism; D004334:Drug Administration Schedule; D007269:Injections, Intra-Arterial; D007980:Levodopa / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D008099:Liver / Q000201:enzymology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D007980:Levodopa; D004296:Dopa Decarboxylase; D002230:Carbidopa