Single-dose pharmacokinetics and pharmacodynamics assessment of oestriol and trimegestone containing vaginal rings in healthy women with childbearing potential.

PURPOSE: To evaluate the pharmacokinetics and pharmacodynamics of oestriol (E3) and trimegestone (TMG) in healthy women after application of three different vaginal rings over 21 days. The vaginal rings had a nominal delivery rate of 0.413/0.050 mg/day (Test 1), 0.311/0.090 mg/day (Test 2) and 0.209/0.137 mg/day (Test 3) E3/TMG. METHODS: Thirty-five healthy women were randomised to receive a single application of Test 1, 2 or 3 (Clinical Trial NCT03343912). The E3 and TMG plasma concentration was determined by LC-MS/MS. Oestradiol (E2) and progesterone (PG) serum concentrations, and bleeding patern were determined as pharmacodynamic parameters. Safety was assessed by evaluation of adverse events and local tolerability. RESULTS: The total and maximum exposure of E3 and TMG increased in a proportional ratio to dose. However, not in a magnitude which was expected from the dose differences for E3. During Test 2 and 3 treatment all E2 and PG values remained on a well suppressed level until end of treatment. E2 and PG serum levels increased distinctly earlier after ring removal with Test 1 compared to Test 2 and 3. Test 3 achieved 95.24% of "no bleeding" days under treatment followed by Test 1 (91.67%), and Test 2 (86.15%). CONCLUSIONS: The Test 3 formulation presented the best dose combination of E3/TMG for contraception. Moreover, all vaginal rings were well tolerated.

Effect on endometrial histology and pharmacokinetics of different dose regimens of progesterone vaginal pessaries, in comparison with progesterone vaginal gel and placebo.

STUDY QUESTION: Which progesterone vaginal pessary dose regimen induces adequate secretory transformation of the endometrium, in comparison with progesterone vaginal gel and placebo? SUMMARY ANSWER: The best secretory transformation of the endometrium was observed during treatment with 400 mg progesterone vaginal pessaries, administered twice daily. WHAT IS KNOWN ALREADY: Vaginally administered progesterone is widely used for luteal phase support (LPS) in assisted reproductive techniques (ART). Although several vaginal formulations using various doses are available, little is known on the impact of formulation and doses at the endometrial level. STUDY DESIGN, SIZE, DURATION: The study had a randomised, observer-blind design and comprised two parts. The participants used study medication during two or three treatment periods, separated by washout periods. Subjects in Part 1 (n = 61 treated) received 200 mg progesterone vaginal pessaries twice daily (bid), 400 mg pessaries bid and the comparator 90 mg progesterone vaginal gel once daily (od) in a 3-way crossover design. Subjects in Part 2 (n = 64 treated) received 100 mg pessaries bid in one period and 400 mg pessaries od in the other period in a 2-way crossover design. A subgroup of these subjects (n = 22 treated) received placebo vaginal pessaries bid in a third period in a non-randomised manner. The study was performed from May 2012 until April 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was performed at a clinical research centre in healthy female volunteers of reproductive age. The subjects used 2 mg estradiol bid for 24 days in each treatment cycle. Progesterone or placebo was administered vaginally from Day 15 onwards during 10 days. In each treatment period, an endometrial biopsy for histological evaluation was performed on Day 23 and pharmacokinetic parameters were determined after the first progesterone dose on Day 15 and after the last dose on Day 24. MAIN RESULTS AND THE ROLE OF CHANCE: Frequencies of (early and late) secretory transformation of the endometrium, i.e. adequate responses, during treatment with 200 mg and 400 mg vaginal pessaries bid were comparable with those during 90 mg vaginal gel treatment (90-94%), whereas lower secretory transformation rates were observed during treatment with 100 mg bid and 400 mg od (64-75%). At the time of the endometrial biopsy in the cycle the late secretory state of the endometrium, which is characteristic of adequate luteal support, was observed more often with 400 mg pessaries bid (90%) than with vaginal gel (82%) and with lower pessary doses (64-78%). Pharmacokinetic parameters after repeated dosing of vaginal pessaries showed a dose-dependent, but not dose-proportional, increase of plasma progesterone levels. The lowest incidence of bleeding and spotting was reported during treatment with 400 mg pessaries bid. LIMITATIONS REASONS FOR CAUTION: The primary outcome parameter, rate of secretory transformation of the endometrium, is a surrogate for endometrial receptivity and for the actual clinical efficacy. WIDER IMPLICATIONS OF THE FINDINGS: Delivery of progestesterone through 400 mg pessaries bid is an effective alternative method for luteal support in ART. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by Actavis Group PTC ehf., Iceland, part of Teva Pharmaceuticals, and L.D. Collins. I.D. and C.K. are directors of Dinox, a contract research organisation. I.K. is Managing Director of Pharmaplex and M.W. is Managing Director of M.A.R.C.O., service organisations involved in organisation/supervision and evaluation/reporting of clinical trials. All received funding for the conduct of the study from Actavis. S.H. and Th.M. are employees of Actavis. TRIAL REGISTRATION NUMBER: EudraCT number 2012-001726-95.

Pharmacokinetics and preliminary efficacy of two vaginal gel formulations of ultra-low-dose estriol in postmenopausal women.

OBJECTIVES: To investigate the pharmacokinetics, safety and preliminary effectiveness of ultra-low-dose estriol vaginal gel formulations (20 µg/g (T1) and 50 µg/g (T2)) compared to Ovestinon® (estriol 500 µg/0.5 g (R)) and placebo in postmenopausal women. METHODS: Forty-three volunteers were randomly assigned to received T1, T2, R or placebo once daily for 21 days. Absorption of estriol after single and multiple administration was analyzed. Cytological changes in the vagina, tolerability and safety were also investigated. RESULTS: Thirty-six women were included in the pharmacokinetic analysis. Systemic absorption was lower with test formulations (AUC0-t: 171.65 ± 80.18 (T1) and 406.75 ± 199.53 (T2) pg/ml × h) than with Ovestinon® (1221.97 ± 549.06 pg/ml × h). Estriol exposure of the test formulations after multiple administration (AUCss: 36.33 ± 30.52 (T1) and 73.71 ± 46.86 (T2) pg/ml × h) was significantly lower than after single-dose administration and not significantly different between them. In contrast, the exposure after repeated administration of Ovestinon® was considerable and not statistically different from levels after single administration. All estriol formulations produced similar improvement in the vaginal maturation value, while placebo showed a small and not significant change. Overall safety and acceptability were good. CONCLUSIONS: Estriol 20 and 50 µg/g formulations, while showing a comparable capacity for reversing vaginal atrophy, present a highly favorable safety profile, producing a very low systemic absorption of estriol and significantly lower than that of Ovestinon®.

Effect of ultra-low-dose estriol and lactobacilli vaginal tablets (Gynoflor®) on inflammatory and infectious markers of the vaginal ecosystem in postmenopausal women with breast cancer on aromatase inhibitors.

This study was a detailed microscopic analysis of the changes of vaginal microflora characteristics after application of 0.03 mg estriol-lactobacilli combination on the vaginal ecosystem in postmenopausal breast cancer (BC) survivors on aromatase inhibitors (AI) with severe atrophic vaginitis. A total of 16 BC women on AI applied daily one vaginal tablet of Gynoflor® for 28 days followed by a maintenance therapy of three tablets weekly for 8 weeks. During four follow up visits a smear from the upper lateral vaginal wall was analysed by phase contrast microscopy at 400 times magnification in order to classify the lactobacillary grades(LBG), bacterial vaginosis (BV), aerobic vaginitis (AV), vulvovaginal candidosis (VVC), proportional number of leukocytes and evidence of parabasal cells and epitheliolysis. LBG improved from 81% LBG-III at entry to 88% LBG-I&IIa after 2 weeks of initial therapy, which further improved upon follow up (p < 0.001). Whereas BV was a rare event, AV was frequent and substantially improved during treatment (p < 0.01). While at entry most patients had moderate or severe AV, after maintenance therapy no patient except one had AV. The number of leukocytes dropped dramatically from a score of 1.78 ± 0.70 to 1.06 ± 0.25 which was consistent till the end of the study (p < 0.01). Parabasal cells dropped from a score of 3.4 ± 0.64 at entry to 1.3 ± 0.60 at the final visit (p trend < 0.01). Starting from a low rate of Candida colonisation of 2/14 (14%), a sudden rise to 7/16 (44%) occurred after 2 weeks, to return back to base levels at subsequent visits. The vaginal use of ultra-low dose estriol and lactobacilli results in rapid and enduring improvement of all markers of the vaginal microflora and epithelial vaginal cell quality in women with breast cancer on AI with dyspareunia. Candida may develop soon after its use, but rapidly disappears again upon their prolonged use. Due to its excellent safety profiles and clinical efficacy we recommend this product as first choice in women on AI with severe dyspareunia.

Ultra-low-dose estriol and Lactobacillus acidophilus vaginal tablets (Gynoflor(®)) for vaginal atrophy in postmenopausal breast cancer patients on aromatase inhibitors: pharmacokinetic, safety, and efficacy phase I clinical study.

Phase I pharmacokinetic (PK) study assessed circulating estrogens in breast cancer (BC) patients on a non-steroidal aromatase inhibitor (NSAI) with vaginal atrophy using vaginal ultra-low-dose 0.03 mg estriol (E3) and Lactobacillus combination vaginal tablets (Gynoflor(®)). 16 women on NSAI with severe vaginal atrophy applied a daily vaginal tablet of Gynoflor(®) for 28 days followed by a maintenance therapy of 3 tablets weekly for 8 weeks. Primary outcomes were serum concentrations and PK of E3, estradiol (E2), and estrone (E1) using highly sensitive gas chromatography-mass spectrometry. Secondary outcomes were clinical measures for efficacy and side effects; microscopic changes in vaginal epithelium and microflora; and changes in serum FSH, LH, and sex hormone-binding globulin. Compared with baseline, serum E1 and E2 did not increase in any of the women at any time following vaginal application. Serum E3 transiently increased after the first application in 15 of 16 women, with a maximum of 168 pg/ml 2-3 h post-insertion. After 4 weeks, serum E3 was slightly increased in 8 women with a maximum of 44 pg/ml. The vaginal atrophy resolved or improved in all women. The product was well tolerated, and discontinuation of therapy was not observed. The low-dose 0.03 mg E3 and Lactobacillus acidophilus vaginal tablets application in postmenopausal BC patients during AI treatment suffering from vaginal atrophy lead to small and transient increases in serum E3, but not E1 or E2, and therefore can be considered as safe and efficacious for treatment of atrophic vaginitis in BC patients taking NSAIs.

Pilot study: absorption and efficacy of multiple hormones delivered in a single cream applied to the mucous membranes of the labia and vagina.

BACKGROUND/AIMS: There is a lack of evidence in the literature supporting vaginal application of a combination hormone-containing cream for local and systemic symptom relief. This pilot study examined the extent of absorption of a single cream containing estriol, estradiol, progesterone, DHEA, and testosterone. METHODS: A combination cream was administered to 12 postmenopausal women in two differing doses over two independent time periods. Following 28 days (arm 1) and an additional 14 days (arm 2), measurement of hormones in saliva and blood and measurements of symptom relief, patient tolerability, and health-related quality of life (HRQoL) were obtained. RESULTS: The dosage and time of evaluation for study arm 1 was not ideal for providing documented increases in hormone levels. HRQoL measurements supported measured improvement in this arm. The second arm did document absorption of the various hormones when given vaginally. CONCLUSION: This study is the first documenting systemic absorption of multiple hormones by both saliva and blood as well as improvement of HRQoL. This therapy was generally well-tolerated with only 2 patients experiencing minor irritation, not necessitating discontinuation. Additional studies in larger numbers of patients will provide better knowledge for clinicians wanting to provide similar therapy at the lowest effective dose.

Specific imaging of hormone-dependent mammary carcinoma in nude mice with [131I]-anti-estriol 3-sulfate antibody.

We tried to put the estrogen metabolite to use in tumor imaging. The antibody against estriol 3-sulfate (E3 3-S), which was one of the major metabolites of estrogen in hormone-dependent mammary carcinoma, was prepared and the tissue distribution and imaging of human breast carcinoma with anti-E3 3-S antibody (Ab) were studied in nude mice. In hormone-dependent breast carcinoma, MCF-7,-bearing nude mice, [125I] anti-E3 3-S Ab localized in tumor with the percentage injected dose/g of 9.29 +/- 3.01 (mean +/- SD). This value was significantly high compared with that in hormone-independent breast carcinoma, MDA-MB-231,-bearing nude mice. At 72 h after the administration of [125I]anti-E3 3-S Ab to MCF-7 bearing mice, tumor/blood, tumor/liver and tumor/muscle ratios were 0.49, 5.02 and 6.83, respectively. These ratios were supposed to be enough for imaging. In radioimmunoscintigraphy, a MCF-7 tumor was clearly visualized at 120 or 168 h post-injection of [131I]anti-E3 3-S Ab.

Comparative pharmacokinetics of two new steroidal estrogens and ethinylestradiol in postmenopausal women.

It was the aim of the study to compare the pharmacokinetic properties of the two new estrogens, ZK 136295 and ZK 115194, with those of ethinylestradiol (EE2) after single intravenous (60 micrograms) and oral (120 and 240 micrograms) administration in 54 postmenopausal women. In particular, our objective was to examine whether one or both compounds were characterized by an improved oral bioavailability with less inter-subject variability than EE2. Drug serum concentrations were determined using specific radioimmunoassays for EE2 and ZK 136295, and a GC/MS/MS-method for ZK 115194. Following i.v. administration of the new estrogens and of EE2, the drugs were rapidly distributed in the body. The mean terminal half-lives were calculated to be 12.3 +/- 12.4, 28.7 +/- 9.6, and 26.1 +/- 11.1 h for ZK 136295, ZK 115194, and EE2 respectively. After oral administration of 120 micrograms, the absolute bioavailability was calculated to be about 40% for ZK 136295 as well as for EE2 with a high inter-individual variation (variation coefficient: 44 and 67%). By doubling the dose, the systemic availability increased dose-dependently for both drugs to about 70% with the same high inter-individual variation. Following single oral administration of 240 micrograms ZK 115194, the absolute bioavailability amounted to 33 +/- 19%. The present study clearly revealed that although the two new estrogens differed considerably in their pharmacokinetic behavior, they demonstrated a reduced and highly variable systemic availability similar to that of EE2.

PIP: Researchers with the pharmaceutical manufacturer Schering AG in Berlin, Germany, conducted a double-blind clinical trial in 54 healthy, postmenopausal women to compare the pharmokinetic properties of two new estrogens (ZK 136295 and ZK 115194) with those of ethinyl estradiol (EE2). Specifically, they examined whether one or both of the new estrogens improved bioavailability with less inter-subject variability than EE2. The dosage included single intravenous (60 mcg) and oral (120 and 240 mcg) administration. ZK 115195 differs from natural estradiol by 14alpha, 17alpha-bridging, which should prevent early metabolic degradation during absorption and passage through the liver. ZK 136295 is the corresponding derivative of endogenous estriol. All three compounds were rapidly distributed throughout the body. ZK 136295 had the shortest mean terminal half-life; ZK 115194 had the longest (12.3 vs. 28.7 hours); and EE2 had a mean terminal half-life of 26.1 hours. Oral administration of 120 mcg effected an absolute bioavailability of about 40% for ZK 136295 and EE2. The inter-individual variation was high (variation coefficient = 44% and 67%) for both compounds. When the oral dose was 240 mcg, systemic availability increased dose-dependently for ZK 136295 and EE2 to around 70% with the same high inter-individual variation. Oral administration of 240 mcg of ZK 115194 effected an absolute bioavailability of about 33%. These findings show that the 14alpha, 17alpha-bridging of estradiol does not result in a higher bioavailability than that achieved by introduction of a 17alpha-ethinyl group. Yet, increasing the dose of ZK 115194 and of EE2 from 120 to 240 mcg increased their absolute bioavailability two-fold. In conclusion, even though the pharmacokinetic behavior of the two new estrogens differed markedly, the two estrogens exhibited a reduced and highly variable systemic availability similar to that of EE2.

Estriol: safety and efficacy.

While conventional hormone replacement therapy provides certain benefits, it is not without significant risks. Estriol has been found to provide some of the protection without the risks associated with stronger estrogens. Depending upon the situation, estriol may exert either agonistic or antagonistic effects on estrogen. Estriol appears to be effective at controlling symptoms of menopause, including hot flashes, insomnia, vaginal dryness, and frequent urinary tract infections. Results of research on its bone-density-maintaining effects have been contradictory, with the most promising results coming from Japanese studies. Estriol's effect on cardiac risk factors has also been somewhat equivocal; however, unlike conventional estrogen prescriptions, it does not seem to contribute to hypertension. Although estriol appears to be much safer than estrone or estradiol, its continuous use in high doses may have a stimulatory effect on both breast and endometrial tissue.

HPLC-fluorescence determination of unconjugated estrogens in pharmaceuticals.

A fluorimetric liquid chromatographic method (lambda(ex) = 280 nm; lambda(em) = 312 nm) was developed for measurements of unconjugated estrogens (estradiol and estriol) in pharmaceutical dosage forms using a reversed-phase column with water acetonitrile at different composition as mobile phase. The in vitro release profiles of three different estradiol transdermal therapeutic systems were determined through a medical-grade silicone rubber subdermal implant material membrane, using a modified Franz diffusion apparatus at 37 degrees C in presence of PEG 400. The HPLC method possesses advantages of rapidity, simplicity and accuracy.

Pharmacokinetics of oestriol after repeated oral administration to dogs.

The aim of the present study was to investigate the pharmacokinetics of oestriol in plasma in the dog after repeated oral administration of oestriol tablets, a preparation intended for the treatment of urinary incontinence in the bitch. The study was performed in six healthy, entire, adult female beagle dogs. The bitches were treated once daily with two tablets, containing 1 mg oestriol per tablet, for seven consecutive days (days 1-7). Blood samples were taken from the jugular vein before treatment, frequently on days 1, 3 and 7 of the treatment period and daily just before (C(trough)) and 1 h after dosing (C(t=1h)). During the washout period samples were taken at a 24 h interval up to four days post-treatment. Oestriol concentrations were determined in plasma by radioimmunoassay. Pharmacokinetic parameters, AUC, C(max) and t(max), were determined from the plasma concentration-time curves using non-compartmental methods. The between animal variation in C(max) and the AUC was high. Individual values of the C(max) varied from 206 pg/ml (day 1) to 1128 pg/ml (day 7) and the AUC(0-24h) from 789 pg x h/ml (day 1) to 5718 pg x h/ml (day 7). t(max) occurred within 1 h. The mean C(trough) value was slightly above the pre-treatment level ( 38+/-2 pg/ml vs. 18+/-5 pg/ml). Within 48 h after the last treatment the concentrations had returned to the pre-treatment values. C(max) and C(trough) did not increase during the treatment period, indicating that no accumulation occurred. A shoulder in the concentration-time curve around 8-12 h after treatment strongly suggested the existence of enterohepatic recirculation (EHR). The average relative contribution of the EHR to the AUC(0-24h) was estimated to be 22%, 38% and 44% on days 1, 3 and 7, respectively. These mean values were calculated from five animals per time point, because one dog failed to show EHR on days 1 and 3 and was therefore excluded from the calculations.

Enterohepatic recycling of estrogen and its relevance with female fertility.

Enterohepatic recycling of estrogen after oral administration of 1 mg non-radioactive estriol was studied in fourteen women selected as the control subjects and ten infertile women in whom the infertility was appearing to be of endocrine origin. The extent of enterohepatic recycling of estriol (E3) during the early follicular phase of menstrual cycle was assessed by monitoring during 48 h the urinary excretion of its two major metabolites i.e; estriol 16 alpha-glucuronide (E3-16 alpha-CG) and estriol-3 glucuronide (E3-3-G). The change in urinary level of E3-3-G with respect to E3-16 alpha-G was considered to reflect the extent of enterohepatic recycling of estriol. Lower values of urinary output of both metabolites in the infertile women as compared with the control subjects and the urinary excretion profile of both metabolites during 48 h after estriol ingestion reveal that the reduced extent of enterohepatic recycling could possibly be one of the factors which contribute towards the incidence of infertility in women.

Bioidentical compounded hormones: a pharmacokinetic evaluation in a randomized clinical trial.

OBJECTIVE: Bioidentical compounded hormone therapy is popular among patients, but providers do not have pharmacokinetic information or dosing guidelines for these preparations. Our objective was to compare the pharmacokinetics of the commonly used compounded preparations with conventional hormonal preparations that are considered bioequivalent in practice. METHODS: We conducted a randomized, blinded, four-arm 16-day clinical trial of forty postmenopausal women assigned to one of three doses of a compounded estrogen cream (Bi-est (80:20); 2.0, 2.5, or 3.0 mg)+compounded oral progesterone 100 mg, or to a conventional estradiol patch (Vivelle-Dot™ 0.05 mg)+Prometrium™ 100mg. Serum levels of estrone, estradiol, estriol, and progesterone were obtained at multiple time intervals during the first 24-h, and at steady-state. RESULTS: Results were analyzable for 37/40 women. Study medications were well tolerated. The AUC at 24h and at steady-state for estrogens remained consistently lower for all doses of Bi-est tested relative to the patch. The difference was statistically significant for Bi-est 2.0mg (AUC-estradiol=181 vs. 956; p<0.001) and 2.5mg (AUC-estradiol=286 vs. 917; p<0.001). Estriol levels remained low in all study arms. Serum progesterone levels were comparable in conventional vs. compounded groups. CONCLUSIONS: This pharmacokinetic trial showed that the currently used doses of compounded hormones yield lower levels of estrogen compared to the standard-dose estradiol patch. To find comparable doses, further studies are needed. This successfully conducted randomized controlled study attests to the feasibility of using a similar design in the setting of a larger clinical trial.

Systemic bioavailability of estriol following single and repeated vaginal administration of 0.03 mg estriol containing pessaries.

UNLABELLED: A prospective monocentric open-label and single-arm trial was performed in 19 postmenopausal women with diagnosed vaginal atrophy. The aim was to determine the extent of a systemic exposure to estriol (CAS 50-27-1). Administration of estriol containing pessaries was daily for 21 days. In order to establish a pharmacokinetic profile after single as well as multiple vaginal doses of 0.03 mg estriol blood samples were taken after the first vaginal administration as well as at day 21 after the last administration. Moreover, in order to control for accumulation additional blood samples were taken predose at days 6, 11 and 16. RESULTS: The initial administration increased the population mean estriol plasma concentration to a maximum of 42.1 pg/ml 1 h after dosing. However, already 12 h after administration the estriol concentration had again dropped below 5 pg/ml (lower limit of quantification) in all patients. Repeated administration did not result in an accumulation of estriol, since 2 h after application of the 21st pessary, the population mean estriol concentration reached a maximum of only 11.9 pg/ml. Moreover, no severe or serious adverse events occurred, and no clinically relevant findings were reported. CONCLUSION: Single vaginal application of pessaries containing 0.03 mg estriol resulted in a very low systemic bioavailability, which decreased even more after multiple dosing confirming a favourable safety profile of low dose pessaries administered daily over 21 days.

Plasma estriol levels after intramuscular injection of estriol and two of its esters.

Twelve female volunteers from Berlin and 9 from Stockholm, all using a contraceptive pill (30 micrograms ethinyl estradiol and 150 micrograms levonorgestrel), received an intramuscular injection of estriol (E3; 1 mg in oil) on day 5 of withdrawal bleeding. Blood samples were collected at increasing time intervals during 4 weeks. Three months later, on day 5 of their withdrawal bleeding, 6 women were given intramuscularly (in oil) estriol 3,17-dipropionate (E3-prop) and 15 women estriol 3,17-dihexanoate (E3-hex). The doses were equivalent to 5 mg of estriol, i.e. 6.94 and 8.90 mg, respectively. Blood samples were collected during a period of 9 weeks. Estriol was analyzed by radioimmunoassay in all plasma samples. The average half-life of E3 ranged from 1.5 to 5.3 h after the administration of E3. It was 12.7 h and between 187 and 221 h after the administration of E3-prop and E3-hex, respectively. The average areas under the curve (in nmol.l-1.h) of E3 were between 82.5 and 161 after the administration of E3-prop or E3-hex, and between 27.1 and 37.9 when E3 had been given. As E3 was administered in a 5-fold lower dose than the esters, the areas under curve appeared to be comparable. Thus, the total exposure to E3 seemed to be almost independent of the type of E3 derivatization, while the time and intensity of exposure were very different.

Equilibrium binding analysis of estrogen agonists and antagonists: relation to the activation of the estrogen receptor.

The equilibrium binding kinetics of the interaction between the estrogen receptor and natural estrogens (estradiol, estriol and estrone), non-steroidal estrogen agonists (11 beta-chloromethyl-estradiol-17 beta, diethyl-stilbestrol, hexestrol) and non-steroidal antiestrogens (clomiphene, tamoxifen) have been characterized. It is proposed that positive cooperative binding of ligands by the estrogen receptor reflects conformational changes in the DNA binding domain of the receptor dimer which increase its affinity to estrogen responsive elements. Weak estrogens fail to induce maximal cooperativity and are less efficient in activating the receptor complex. Antiestrogens, that inhibit the [3H]estradiol-induced cooperative binding, suppress the activation of the receptor and inhibit its nuclear interactions. Another class of antiestrogens (e.g., 4-hydroxytamoxifen) interacts with the receptor in a manner that is indistinguishable from the cooperative interaction of estradiol, and the resulting complex may also exhibit increased affinity for estrogen responsive elements. However, these complexes cannot activate transcription, presumably due to an aberrant induction of transcription-activating domain in the receptor. We suggest that the positive cooperativity of the estrogen receptor results from conformational changes in the receptor that are transmitted also to the DNA binding domain. On the other hand, conformational changes in the transcription activating domain are not revealed by equilibrium binding kinetics. Thus, compounds that block the positive cooperative binding of [3H]estradiol by the receptor act as antiestrogens. Other compounds that interact cooperatively with the receptor can activate the receptor DNA binding domain, however, they may or may not induce the full array of conformational changes required for transactivation of transcription.

Estrogen replacement in postmenopausal women: are we currently overdosing our patients?

As there are no proven optimal serum estradiol levels, we sought to evaluate the pharmacokinetic profiles of serum estradiol levels following a single oral dose of 2 mg estradiol and 1 mg of estriol (Trisequens) among 26 surgically induced, postmenopausal patients. Their serum estradiol levels were periodically measured over 24 h following oral administration of the drug. They were divided into two groups according to the computed hourly mean estradiol values: group A, < 250 pg/ml/h ( < 918 pmol/l/h) and group B, > 250 pg/ml/h ( > 918 pmol/l/h). The mean peak estradiol concentrations were noted 2 h after drug administration and amounted to 595 +/- 190 pg/ml (2,184 +/- 697 pmol/l) in the entire cohort; 435 +/- 117 pg/ml (1,597 +/- 430 pmol/l) in group A and 712 +/- 142 pg/ml (2,614 +/- 521 pmol/l) in group B (p < 0.001). The mean total area under the curve in group A was 4,887 pg/ml (17,940 pmol/l), which was significantly lower than that of 7,995 +/- 652 pg/ml/24 h (29,350 +/- 2,393 pmol/l/24 h) found for group B (p < 0.001). The mean body mass index showed a significant difference (p < 0.003) between group A and group B (29.4 +/- 0.56 vs. 24.3 +/- 0.24). We found that 57% of our patients were exposed to excessively high levels of estradiol during the 24-hour period following drug ingestion. We advise monitoring estradiol levels and individualizing estrogen replacement therapy, to avoid the long-term exposure of postmenopausal patients to superphysiological estradiol levels.

[Cross-over comparison of the pharmacokinetics of estradiol during hormone replacement therapy with estradiol valerate or micronized estradiol]. / Uberkreuz-Vergleich der Pharmakokinetik von Estradiol unter der Hormonsubstitution mit Estradiolvalerat oder mikronisiertem Estradiol.

OBJECTIVE: The aim of this randomized cross-over study was the comparison between a sequential 28-day hormone replacement therapy (HRT) using micronized estradiol and a cyclic 21-day HRT using estradiol valerate with regard to the pharmacokinetics of estradiol. - MATERIAL AND METHODS: Fifty postmenopausal women were randomly assigned to be treated either with Trisequens(R) for 28 days or with Sisare(R) for 21 days. After a wash-out cycle, the women were treated for one cycle with the other preparation in a cross-over fashion. The pharmacokinetic profile of the serum concentrations of estradiol was measured on day 1, 21 and 28 each immediately before and 1, 2, 4, 6, 8, and 10 hours after intake of a tablet, and the AUC (area under the curve) was calculated. - RESULTS: The serum concentrations of estradiol increased from a mean of 10 pg/ml up to 40 pg/ml (Trisequens(R)) and 30 pg/ml (Sisare(R)) on day 1, and to 80 pg/ml (Trisequens(R)) and 60 pg/ml (Sisare(R)) on day 21, and declined to 40 pg/ml (Trisequens(R)) and 10 pg/ml (Sisare(R)) on day 28. The AUC as calculated from both treatment cycles, was significantly higher on day 1, 21, and 28 during treatment with Trisequens(R) than with Sisare(R). This difference was, however, not signifcant on day 1 and 21 of the first treatment cycle. - CONCLUSION: During treatment with 2 mg micronized estradiol the serum concentrations are significantly higher than with 2 mg estradiol valerate. On day 28 of treatment with Sisare(R), the estradiol levels decline to baseline values, while using Trisequens(R) they remain in the range of those measured on day 1.

When applied to facial skin, does estrogen ointment have systemic effects?

We examined cytological vaginal smears of 17 women before and after three months of dermal estrogen (1 g of 0.01% estradiol ointment or 0.3% estriol ointment once daily), applied to the face for dermatological indications. The mean age was 57.1 +/- 7.6 years (range from 46 to 66). Seven women had estrogenic smears (more than 10% superficial cells) before therapy. Nine women were treated with 0.01% estradiol ointment and 8 were treated with 0.3% estriol ointment. Both groups had gynecological examinations including cervical and vaginal smears before and after treatment and also monthly measurements of serum follicle-stimulating hormone, prolactin and estradiol levels. Serum hormone levels and the appearance of vaginal smears showed no significant change during treatment.