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At least 19 recordsLinked to original sources
PubMed1978

Ethinyl estradiol in peripheral plasma after oral administration of 30 microgram and 50 microgram to women.

Plasma levels of ethinyl estradiol were measured by radioimmunoassay in five women after oral administration of 30 microgram and of 50 microgram of ethinyl estradiol. Peak levels of ethinyl estradiol were mostly observed within two hours after the tablet intake. The peak concentrations found were 50--90 pg and 95--135 pg for the two doses administered. Twenty-four hours after the administration of the tablets, the plasma concentration of ethinyl estradiol did not exceed the plasma blank values (25 pg/ml) in most women.

Administration, Oral↗
PubMed1979

Some estrogenic effects of two oral contraceptives consisting of norgestrel and two different doses of ethynylestradiol.

Some biological and biochemical effects (i.e. KPI, cervical mucus, SHBG and ceruloplasmin) as well as serum ethynylestradiol and serum norgestrel, following the use of two oral contraceptives containing the same amount of norgestrel (dl-norgestrel 0.5 mg) and either 30 microgram or 50 microgram of ethynylestradiol were compared. There was no difference in the clinical features in either group of patients. There was a statistically significant difference in the levels of unconjugated ethynylestradiol but not in the other biochemical parameters studied. It is concluded that the absence of any such difference might be attributable to the strong antiestrogenic effects of dl-norgestrel.

Adolescent↗
PubMed1979

An investigation of the pharmacokinetics of ethynylestradiol in women using radioimmunoassay.

A radioimmunoassay for ethynylestradiol (EE) which is applicable to plasma samples obtained from women, who have taken a combination type oral contraceptive, has been developed and fully validated. Plasma concentration of EE rise to a peak of 128 pg/ml following the oral administration of 50 microgram EE. Following the intravenous administration of the same dose of EE, plasma concentrations of the steroid declined biexponentially, the two half-lives being 0.83 and 6.75 hours. Comparison of the results of the intravenous and oral administration of the steroid suggested that its oral bioavailability is 42%. Although EE thus has a lower bioavailability than norethindrone, the pharmacokinetics of the two steroids, as reflected by half-lives, plasma clearance and volume of distribution, are very similar. The occurrence of a secondary peak in plasma at around 12 hours after dosing gave strong evidence that EE undergoes enterohepatic circulation in women; an event that may have considerable clinical significance.

Administration, Oral↗
PubMed1979

Accumulation of ethinylestradiol in blood and endometrium of women taking oral contraceptives: the sequential therapy.

A radioimmunoassay to quantitate ethinylestradiol (EE-2) in both plasma and endometrium is described. In 29 women under sequential oral contraceptive therapy (chlormadinone acetate, 2 mg, plus mestranol, 80 microgram) for 6 to 84 months, a single blood sample and a single endometrial sample were simultaneously obtained on different days of the pseudomenstrual cycle. In 24 women under 40 years of age the mean plasma EE-2 concentrations were similar during the first (989 +/- 94 pg/ml) and the second half of the cycle (1053 +/- 186 pg/ml) (P greater than 0.05). A similar finding was observed with regard to mean endometrial EE-2 concentrations (3.55 +/- 2.1 and 5.89 +/- 1.7 microgram/gm of wet tissue, respectively). On the other hand, five women over 40 years of age had plasma EE-2 concentrations similar to those of the previous group, but the mean endometrial EE-2 concentrations was 0.9 +/- 0.6 microgram/gm of wet tissue (P less than 0.05). Although plasma follicle-stimulating hormone and luteinizing hormone did not show midcycle peak values, complete suppression of both gonadotropins was not observed. These results show that endometrium has a great ability to concentrate EE-2, and this ability seems to be greater in women below age 40 than above. Whether or not this observation might be related to the known higher incidence of endometrial cancer in women less than 40 years old who have been under chronic sequential oral contraceptive therapy cannot be disclosed from this limited number of determinations.

Adolescent↗
PubMed1975

The urinary metabolites of 17alpha-ethynylestradiol-9alpha,11xi-3H in women. Chromatographic profiling and indentification of ethynyl and non-ethynyl compounds.

Metabolites of 17alpha-ethynylestradiol (EE2) were obtained from human urine following ingestion of tritium-labeled EE2. Over 95% of the recovered activity was found as conjugated steroids and these were separated into four groups by chromatography of the urine extract on Sephadex LH-20 with chloroform-methanol (1/1) + 0.01M NaCl. The two major conjugate fractions appeared to be almost exclusively glucosiduronates. Enzymatic hydrolysis liberated at least ten different EE2 metabolites as shown by chromatography on Sephadex LH-20 with benzene-methanol (85/15). After additional separation and purification of these metabolites, positive identification was obtained for nine radioactive compounds by either gas liquid chromatography-mass spectrometry or reverse-isotope recrystallization. Five were ethynyl compounds: EE2, 2-MeO EE2, 16beta-OH EE2, 2-OH EE2 and 6alpha-OH EE2. The other four were de-ethynylated estrogens: estrone, estradiol-17beta, estriol, and 2-Me-O-estradiol-17beta.

Chromatography, Gas↗
PubMed1977

Interaction of rifampicin treatment with pharmacokinetics and metabolism of ethinyloestradiol in man.

[6,7-3H]Ethinyloestradiol (50 microng) was administered intravenously to volunteers and the free extractable ethinyloestradiol in the plasma was measured. The compound showed a biphasic plasma decline. The half-life of the second phase was 7.5+/-1.7 (SD) hours. Administration of rifampicin (600 mg for 6 days) shifted the half-life of ethinyloestradiol to 3.3+/-0.9 h while the apparent volume of distribution for the second phase of elimination was not changed. When [2,4,6,7-3H]ethinyloestradiol (100 microng) was administered orally, some of the tritium was released by oxidative metabolism from the steroid and transformed to tritiated water (HTO) which equilibrated with whole body water. This portion, normally 7.17+/-1.66% of the tritium dose, was increased by previous administration of rifampicin to 10.62+/-2.27%. The initial rate of oxication of [2,4,6,7-3H]ethinyloestradiol was increased more than twofold by rifampicin treatment. The results are consistent with previous findings that rifampicin induces the oestrogen-2-hydroxylase in the endoplasmic reticulum of human liver, and explain the reduced effectiveness of ethinyloestradiol in oral contraceptives, if the patients are treated with rifampicin.

Administration, Oral↗
PubMed1977

Oestrogenic activity of oestradiol-decanoate after oral administration to rodents.

Oestradiol-decanoate, dissolved in arachis oil and orally administered to rodents, produces oestrogenic effects. Compared on a molecular basis the ester has 0.1-1.0 times the activity of ethinyl oestradiol, dependent on the species and the parameter studied. The effects of oestradiol-decanoate are less or absent when the oil is omitted. It is likely that absorption of the steroid ester takes place via the intestinal lymphatics in conjunction with the oil.

Administration, Oral↗
PubMed1979

Mestranol.

Explore the source record for details and available documents.

Animals↗
PubMed1977

[Studies on the excretion of estrogen in cows following oral and percutaneous (pour-on) administration of chlormadinone acetate].

The oestrogen levels were assessed in 180 urine samples taken from 20 cows. The animals had received over 15 days 40 mg one-per-cent oily solution of chloromadinone acetate. The solution had been applied orally or by pour-on methods. The curves of oestrogen excretion were identical for both methods of application, both during and after completed administration. In other words, the effect obtainable from pour-on application is just as good as that obtainable from oral administration.

Administration, Oral↗