Pathway of Absorption of Orally Administered Ethynylestradiol-3-Cy-clopentyl Ether ∗ in the Rat as Influenced by Vehicle of Administration. †

Summary

The pathway of transport of labelled ethynylestradiol (EE) or its 3-cyclo-pentyl ether (EECPE) has been studied following oral administration to rats.

The data on lymphatic transport of EE, whether administered as aqueous suspension or dissolved in a lipid vehicle, agree well with previous findings on other steroidal compounds which similarly indicate that: a) the portal system is the major, if not the exclusive pathway of transport of many steroids and b) the pathway of transport is independent of the vehicle of administration. By contrast, the lymphatic transport of EECPE could be significantly increased by use of a lipid vehicle indicating that not only the chemical nature of the compound but also the nature of the vehicle plays an important role in determining pathway of transport.