A comparison of oral and rectal absorption of L-dopa esters in rats and mice.

Journal Article (Journal Article)

Short-chain alkyl esters of L-dopa were administered to rats and mice via oral and rectal routes. Plasma L-dopa esters and L-dopa were determined in the systemic and portal circulation by HPLC. A comparison of isopropyl, butyl, and 4-hydroxybutyl esters of L-dopa demonstrated significantly higher levels of the esters in both systemic and portal blood samples following rectal administration than following oral administration. In most cases, oral administration resulted in nondetectable (less than 0.01 micrograms/ml) levels of the esters in plasma. Correspondingly, the plasma levels of L-dopa itself were consistently higher following rectal administration. At very high oral doses (500 mg L-dopa equivalents/kg body weight), systemic plasma levels of the butyl ester could be detected (1.25 micrograms/ml at 10 min), which might indicate saturation of the esterase activity of the small intestine. These studies indicate that the systemic availability of L-dopa from short-chain alkyl esters of L-dopa may be best optimized by rectal administration, which avoids the relatively high esterase activity characteristic of the small intestine.

Full Text

Duke Authors

Cited Authors

  • Fix, JA; Alexander, J; Cortese, M; Engle, K; Leppert, P; Repta, AJ

Published Date

  • April 1990

Published In

Volume / Issue

  • 7 / 4

Start / End Page

  • 384 - 387

PubMed ID

  • 2362912

International Standard Serial Number (ISSN)

  • 0724-8741

Digital Object Identifier (DOI)

  • 10.1023/a:1015823523388


  • eng

Conference Location

  • United States