Dose-dependent Pharmacokinetics of Laevodopa and its Metabolites in the Rat

Content Provider	Scilit
Author	Cheng, Lawrence K. Fung, Ho-Leung
Copyright Year	1976
Description	Journal: Xenobiotica 1. Plasma levels of total radioactivity, unchanged laevodopa, dopamine, 3-O-methyldopa and non-amino phenolic acids were measured in rats treated orally with [3H]laevodopa at total laevodopa doses of 1, 10, 20 and 100mg/kg while the radioactive dose was maintained at 100muCi/kg for all animal groups. 2. Within the dosage range studied, non-linear pharmacokinetics were observed for unchanged laevodopa, non-amino phenolic acids and dopamine but not for 3-O-methyldopa. 3. The area under the plasma concentration-time curve for laevodopa increased exponentially with linear increments in the oral dose. This non-linear increase in laevodopa bioavailability is consistent with the hypothesis that high oral doses of laevodopa are required to saturate gastro-intestinal metabolism of the drug. 4. At the lower doses (1 and 20 mg/kg), only 2-3% of total radioactivity could be attributed to dopamine. At 100mg/kg, the dopamine metabolite fraction amounted to about 1/3 of total radioactivity in the plasma.
Related Links	http://www.tandfonline.com/doi/pdf/10.3109/00498257609151633
Ending Page	248
Page Count	12
Starting Page	237
ISSN	00498254
e-ISSN	13665928
DOI	10.3109/00498257609151633
Journal	Xenobiotica
Issue Number	4
Volume Number	6
Language	English
Publisher	Informa UK Limited
Publisher Date	1976-01-01
Access Restriction	Open
Subject Keyword	Journal: Xenobiotica Pharmacokinetics Total Radioactivity
Content Type	Text
Subject	Health, Toxicology and Mutagenesis Medicine Biochemistry Toxicology Pharmacology