Title: Oral bioavailability of 17β-estradiol and various ester prodrugs in the rat
Abstract: The oral bioavailability of 17β-estradiol is only about 10% in humans due to extensive first-pass metabolism. The feasibility of depressing this metabolism and hence improving the systemic bioavailability by the prodrug approach was examined using a rat model. The prodrugs studied included the 17-acetate, 17-valerate, 17-cypionate, 3-benzoate, 3-acetylsalicylate and 3-anthranilate esters of 17β-estradiol. Following oral administration to rats the systemic bioavailability of 17β-estradiol was found to be 4.3% whereas the bioavailability observed after administration of the esters ranged from 1.0 to 7.6%. This finding suggests that the esters are unable to protect the parent drug against first-pass metabolism as assessed in the rat. The poor bioavailability observed with the v-acetylsalicylate and 3-anthranilate esters contrasts greatly with previously reported findings with these ester prodrugs in dogs.
Publication Year: 1991
Publication Date: 1991-09-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 15
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