PMID: 932965Jun 1, 1976

Influence of route of administration on physiological availability of levodopa in dogs

Journal of Pharmaceutical Sciences
S CotlerS A Kaplan


The physiological basis for the reduced levodopa bioavailability following oral administration was investigated. Four dogs received single 25-mg/kg doses of 14C-levodopa on three separate occasions in a crossover fashion via hepatoportal catheter, intravenous, and oral administrations. Plasma and urine specimens were analyzed for intact levodopa and total radioactivity. The ratios of areas under the plasma concentration-time curves following hepatoportal and intravenous adminstrations were close to unity, and the shapes of the curves were virtually identical. Following oral administration, however, significant reductions in the areas under the plasma concentration-time curves were observed. These data indicate that the physiologically impaired bioavailability of orally administered levodopa occurs almost exclusively as a result of metabolic degradation within the GI lumen and/or gut wall.


Dec 19, 1973·Naunyn-Schmiedeberg's Archives of Pharmacology·A K GranerusA Svanborg
Apr 1, 1974·Journal of Pharmacokinetics and Biopharmaceutics·H G BoxenbaumR M Elashoff
Apr 13, 1973·Nature·D N WadeJ L Morris
Jan 1, 1973·Journal of Neural Transmission·W BirkmayerP Riederer
Jul 1, 1973·Chemical & Pharmaceutical Bulletin·T Suzuki, Y Saito
Jul 1, 1971·Journal of Pharmaceutical Sciences·C B CoutinhoT Crews
Nov 1, 1971·Biochemical Pharmacology·L Rivera-CalimlimL Lasagna
Jul 6, 1971·Annals of the New York Academy of Sciences·J R BianchineL Lasagna
May 1, 1971·European Journal of Clinical Investigation·L Rivera-CalimlimJ R Bianchine


Jan 1, 1980·European Journal of Clinical Pharmacology·M A EvansN Saines
Jan 1, 1991·European Journal of Clinical Pharmacology·M ContinA Baruzzi
Jan 1, 1981·Pharmacology & Therapeutics·J G Wagner
Dec 1, 1982·Psychiatry Research·H G WestenbergH M van Praag
May 9, 2002·International Journal of Pharmaceutics·Babita S Gupta, Ashok K Tiwary
Jan 1, 1983·Acta Neurologica Scandinavica. Supplementum·J D Parkes
Jul 1, 1988·Journal of Pharmaceutical Sciences·K MurataM Samejima
Nov 1, 1982·Acta Pharmacologica Et Toxicologica·I B Lindén, S Niemi

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