90 YEARS OF PROGESTERONE: Selective progesterone receptor modulators in gynaecological therapies.

Abnormal uterine bleeding (AUB) is a chronic, debilitating and common condition affecting one in four women of reproductive age. Current treatments (conservative, medical and surgical) may be unsuitable, poorly tolerated or may result in loss of fertility. Selective progesterone receptor modulators (SPRMs) influence progesterone-regulated pathways, a hormone critical to female reproductive health and disease; therefore, SPRMs hold great potential in fulfilling an unmet need in managing gynaecological disorders. SPRMs in current clinical use include RU486 (mifepristone), which is licensed for pregnancy interruption, and CDB-2914 (ulipristal acetate), licensed for managing AUB in women with leiomyomas and in a higher dose as an emergency contraceptive. In this article, we explore the clinical journey of SPRMs and the need for further interrogation of this class of drugs with the ultimate goal of improving women's quality of life.

Sorption and desorption of seven steroidal synthetic progestins in five agricultural soil-water systems.

Manure fertilization and wastewater irrigation can introduce the biologically potent synthetic progestins into agricultural soils, causing endocrine disruption in organisms of nearby surface waters. Therefore, this study investigated the sorption and desorption potential of etonogestrel, medroxyprogesterone, gestodene, norgestrel, cyproterone acetate, levonorgestrel, and dienogest in five agricultural soil-water systems. Sorption data were well-described by the linear sorption model. In most batch systems, cyproterone acetate exhibited the highest affinities for soils, followed by etonogestrel, medroxyprogesterone, levonorgestrel, gestodene, norgestrel, and dienogest. The sorption magnitudes (logKoc or logKd) were significantly correlated with the progestin hydrophobicities (R2 = 0.72-0.86, p < 0.05). The Kd values of the progestins were also significantly correlated with organic carbon content and pore volumes of the soils (R2 = 0.68-0.98, p < 0.05). In addition, 0.5 M urea resulted in 3-19% decreases in Kd values of the progestins. Taken together, these data indicated that hydrophobic partitioning interaction, hydrogen bonding interaction, and pore filling were the sorption mechanisms for the progestins in soil-water systems. No significant desorption hysteresis was observed for the progestins, indicating that they can be readily desorbed under rainfall or irrigation events. Based on the sorption and desorption data, we estimated the dynamic transport of the progestins in conventional agricultural management systems, and predicted the concentrations of the progestins as a function of soil-sorbed concentration, water-soil ratio, and dilution factor of receiving waters. This study will improve the understanding of the risks posed by the progestins under field-scale hydrological conditions.

EC313-a tissue selective SPRM reduces the growth and proliferation of uterine fibroids in a human uterine fibroid tissue xenograft model.

Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p < 0.01). Estradiol (E2) induced proliferation was blocked significantly in EC313-treated xenograft fibroids (p < 0.0001). Uterine weight was reduced by EC313 treatment compared to UPA treatment. ER and PR were reduced in EC313-treated groups compared to controls (p < 0.001) and UPA treatments (p < 0.01). UF specific desmin and collagen were markedly reduced with EC313 treatment. The partial PR agonism and no signs of unopposed estrogenicity makes EC313 a candidate for the long-term treatment for UFs. Docking studies have provided a structure based explanation for the SPRM activity of EC313.

Isolation, synthesis, and cytotoxicity evaluation of two impurities in nomegestrol acetate.

Nomegestrol acetate (NOMAc) is a synthetic progesterone analog and classified as a fourth-generation progestin. It has been approved in many countries for oral contraception, hormonal replacement therapy (HRT), and treatment of various gynecological disorders. There are several synthetic routes reported for the synthesis of NOMAc and they all share the very similar last three to five steps toward the conversion of 6-methylene to 6-methyl-6,7-unsaturated structure. Therefore the final product from different processing routes may have similar impurity profiles. In the analysis of NOMAc, we identified two impurities, impurity A (listed in EP 8.0) and impurity B (not specified in EP 8.0). Both impurities were further confirmed by synthesis. In addition, both impurities and NOMAc were evaluated for their in vitro cytotoxicities against L02 liver cells, mesenchymal stem cells, MCF-7 breast cancer cells, and C33A cervical cancer cells. These three analogs are not cytotoxic to the four cell lines at low concentrations (<20 µM). NOMAc and impurity A showed cytotoxicity to L02, MCF-7, and C33A cells at high concentrations, while impurity B did not show significant cytotoxicity to any of the cell lines tested.

Menopausal Symptom Relief and Side Effects Experienced by Women Using Compounded Bioidentical Hormone Replacement Therapy and Synthetic Conjugated Equine Estrogen and/or Progestin Hormone Replacement Therapy, Part 3.

The use of compounded bioidentical hormone replacement therapy by menopausal women has become a popular alternative to traditional synthetic conjugated equine estrogen and progestin hormone replacement therapy due to safety concerns raised by recent studies. However, due to the lack of randomized, large-scale trials to evaluate the efficacy and side-effect profile of compounded bioidentical hormone replacement therapy many healthcare providers are reluctant to prescribe such therapy. The purpose of this study was to compare women's menopausal symptom relief and side effects experienced when using compounded bioidentical hormone replacement therapy and traditional hormone replacement therapy. A descriptive comparative design was used. Inferential and descriptive statistical procedures including a paired difference t-test, two-sample t-test, and f-tests (percentage, mean, standard deviation, frequency) were run on the Statistical Package for the Social Sciences. The framework used to guide this study was Lenz and Pugh's Theory of Unpleasant Symptoms. Surveys were distributed once to a convenient sample of women aged 35 and older when they dropped off or picked up their prescriptions at a pharmacy. Of the 216 surveys distributed, 70 were returned from those women taking compounded bioidentical hormone replacement therapy and 53 from traditional hormone replacement therapy. The survey contained 15 questions pertaining to age, duration of hormone replacement therapy, type and formulation of hormone replacement therapy, reasons for initiating hormone replacement therapy, symptoms before and one month after hormone replacement therapy, and side effects related to hormone replacement therapy. Included in part 1 of this series of articles was the introduction to the study conducted and the results of the literature review that was conducted for the purpose of examining the current data related to the topic of hormone replacement therapy. Part 2 provided a brief discussion on the significance of this study to nursing and provided the methods used in this study. The results and conclusion of this study are provided within this article.

Menopausal Symptom Relief and Side Effects Experienced by Women Using Compounded Bioidentical Hormone Replacement Therapy and Synthetic Conjugated Equine Estrogen and/or Progestin Hormone Replacement Therapy, Part 2.

The use of compounded bioidentical hormone replacement therapy by menopausal women has become a popular alternative to traditional synthetic conjugated equine estrogen and progestin hormone replacement therapy due to safety concerns raised by recent studies. However, due to the lack of randomized, large-scale trials to evaluate the efficacy and side-effect profile of compounded bioidentical hormone replacement therapy many healthcare providers are reluctant to prescribe such therapy. The purpose of this study was to compare women's menopausal symptom relief and side effects experienced when using compounded bioidentical hormone replacement therapy and traditional hormone replacement therapy. A descriptive comparative design was used. Inferential and descriptive statistical procedures including a paired difference t-test, two-sample t-test, and f-tests (percentage, mean, standard deviation, frequency) were run on the Statistical Package for the Social Sciences. The framework used to guide this study was Lenz and Pugh's Theory of Unpleasant Symptoms. Surveys were distributed once to a convenient sample of women aged 35 and older when they dropped off or picked up their prescriptions at a pharmacy. Of the 216 surveys distributed, 70 were returned from those women taking compounded bioidentical hormone replacement therapy and 53 from traditional hormone replacement therapy. The survey contained 15 questions pertaining to age, duration of hormone replacement therapy, type and formulation of hormone replacement therapy, reasons for initiating hormone replacement therapy, symptoms before and one month after hormone replacement therapy, and side effects related to hormone replacement therapy. Included in part 1 of this series of articles was the introduction to the study conducted and the results of the literature review that was conducted for the purpose of examining the current data related to the topic of hormone replacement therapy. Part 2 provides a brief discussion on the significance of this study to nursing and provides the methods used in this study. The results of this study will be summarized in forthcoming articles in this series.

Development of megestrol acetate solid dispersion nanoparticles for enhanced oral delivery by using a supercritical antisolvent process.

In the present study, solid dispersion nanoparticles with a hydrophilic polymer and surfactant were developed using the supercritical antisolvent (SAS) process to improve the dissolution and oral absorption of megestrol acetate. The physicochemical properties of the megestrol acetate solid dispersion nanoparticles were characterized using scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and a particle-size analyzer. The dissolution and oral bioavailability of the nanoparticles were also evaluated in rats. The mean particle size of all solid dispersion nanoparticles that were prepared was <500 nm. Powder X-ray diffraction and differential scanning calorimetry measurements showed that megestrol acetate was present in an amorphous or molecular dispersion state within the solid dispersion nanoparticles. Hydroxypropylmethyl cellulose (HPMC) solid dispersion nanoparticles significantly increased the maximum dissolution when compared with polyvinylpyrrolidone K30 solid dispersion nanoparticles. The extent and rate of dissolution of megestrol acetate increased after the addition of a surfactant into the HPMC solid dispersion nanoparticles. The most effective surfactant was Ryoto sugar ester L1695, followed by D-α-tocopheryl polyethylene glycol 1000 succinate. In this study, the solid dispersion nanoparticles with a drug:HPMC:Ryoto sugar ester L1695 ratio of 1:2:1 showed >95% rapid dissolution within 30 minutes, in addition to good oral bioavailability, with approximately 4.0- and 5.5-fold higher area under the curve (0-24 hours) and maximum concentration, respectively, than raw megestrol acetate powder. These results suggest that the preparation of megestrol acetate solid dispersion nanoparticles using the supercritical antisolvent process is a promising approach to improve the dissolution and absorption properties of megestrol acetate.

Long-acting injectable hormonal dosage forms for contraception.

Although great efforts have been made to develop long-acting injectable hormonal contraceptives for more than four decades, few long-acting injectable contraceptives have reached the pharmaceutical market or even entered clinical trials. On the other hand, in clinical practice there is an urgent need for injectable long-acting reversible contraceptives which can provide contraceptive protection for more than 3 months after one single injection. Availability of such products will offer great flexibility to women and resolve certain continuation issues currently occurring in clinics. Herein, we reviewed the strategies exploited in the past to develop injectable hormonal contraceptive dosages including drug microcrystal suspensions, drug-loaded microsphere suspensions and in situ forming depot systems for long-term contraception and discussed the potential solutions for remaining issues met in the previous development.

Bimodal binding and free energy of the progesterone receptor in the induction of female sexual receptivity by progesterone and synthetic progestins.

Synthetic progestins (SPs) are used for regulation of fertility, contraception and hormone replacement therapy. The acetylated medroxyprogesterone (MPA), megestrol (MGA) and chlormadinone (CLA) are related to progesterone (P). Other SPs are 19-nortestosterone derivatives such as: norethisterone (NET), norethynodrel (NED) or the 13-ethyl gonane, levonorgestrel (LNG). We studied MPA, NET, NED and LNG in a dose-response manner to induce sexual receptivity in rats. Results showed that MPA, NET and NED act as partial agonists, with similar or lower potency than P. However, LNG is a full agonist. Additionally, the molecules of MPA, MGA, CLA, NET, NED, LNG, and P, were submitted to computer calculations at ab initio quantum mechanics theory, to obtain their electronic structure and molecular properties. The aim was to correlate their behavioral effect with their physicochemical properties. In addition, the crystals of P, NET and LNG bound to the progesterone receptor (PR) were studied. The PR crystallizes as a dimer forming two monomers (mA and mB), in which Gln725 interacts in either of two possible ways with the C3-carbonyl pharmacophore of progestins. P binds differentially to both PR monomers, while NET binds exclusively as mA and LNG binds only as mB in both monomers with no difference. Energetically, binding of LNG and P to mB, is more favorable than that of NET and P to mA. Consequently, this bimodal mechanism increases the action possibilities of SPs on biological systems. Interestingly, progestin potency depends mostly on local molecular structure and electronic features, prevailing over total molecular properties.

Preclinical pharmacological profile of nomegestrol acetate, a synthetic 19-nor-progesterone derivative.

BACKGROUND: Nomegestrol acetate (NOMAC), a synthetic progestogen derived from 19-nor-progesterone, recently completed clinical trials for use with 17beta-estradiol in a new monophasic combined oral contraceptive. In this review, published as well as previously unpublished preclinical studies that detail the effects of NOMAC on estrogenic, progestogenic, and androgenic systems, as well as mineralocorticoid, glucocorticoid, bone, and metabolic indices are described. METHODS: In vitro assays to determine NOMAC structure-activity relationships used tissue derived from rat uteri. Transactivation profiles were performed using Chinese hamster ovary (CHO) cells transfected with cDNAs encoding human steroid receptors. Estrogenic and anti-estrogenic activities were monitored in vivo in rats as well as in vitro in human breast cancer cells. Standard in vivo techniques were used in rats to determine progestational activity; antigonadotropic, androgenic, mineralocorticoid, and glucocorticoid activities; as well as effects on bone and other metabolic indices. Ovulation inhibition was monitored in rats and primates. NOMAC's effects on cardiovascular systems were determined in dogs and primates. RESULTS: NOMAC was without significant agonistic or antagonistic activity for estrogen receptor alpha or beta in vitro, and inhibited ovulation in rats and monkeys (2.5 mg/kg and 1 mg/kg, respectively). NOMAC lacked androgenic, antimineralocorticoid, glucocorticoid, and metabolic activity and exhibited moderate anti-androgenic activity in rats. NOMAC did not affect bone mineral density (BMD) in rats or hemodynamic and electrophysiologic parameters in dogs and primates. CONCLUSIONS: NOMAC is a selective progestogen structurally similar to progesterone that has modest anti-androgenic activity and does not affect lipid or carbohydrate metabolism, BMD, or many cardiovascular parameters in selected animal models.

Nomegestrol acetate/estradiol: in oral contraception.

Nomegestrol acetate/estradiol is a combined oral contraceptive with approval in many countries. This fixed-dose combination tablet contains nomegestrol acetate, a highly selective progestogen, and estradiol, a natural estrogen. It is the first monophasic combined oral contraceptive to contain estradiol, and is taken in 28-day cycles, consisting of 24 active therapy days with 4 placebo days (i.e. 24/4-day cycles). In two large, 1-year, randomized, open-label, multicentre, phase III trials in healthy adult women (aged 18-50 years), nomegestrol acetate/estradiol was at least as effective as drospirenone/ethinylestradiol as contraceptive therapy, as the pregnancy rates in women aged 18-35 years (primary efficacy population) in terms of the Pearl Index (primary endpoint) were numerically lower with nomegestrol acetate/estradiol, although the between-group difference was not statistically significant. In both trials, nomegestrol acetate/estradiol was given in a 24/4-day cycle, and drospirenone/ethinylestradiol was given in a 21/7-day cycle. The criteria for using condoms in case of forgotten doses were less stringent in the nomegestrol acetate/estradiol group than in the drospirenone/ethinylestradiol group. Nomegestrol acetate/estradiol therapy for up to 1 year was generally well tolerated in healthy adult women, with an acceptable tolerability profile in line with that expected for a combined oral contraceptive. The most commonly reported adverse events were acne and abnormal withdrawal bleeding (most often shorter, lighter or absent periods). Overall, compared with drospirenone/ethinylestradiol, nomegestrol acetate/estradiol appeared to be associated with less favourable acne-related outcomes, and shorter, lighter or absent periods.

Molecular mechanisms of steroid receptor-mediated actions by synthetic progestins used in HRT and contraception.

Synthetic progestins are used by millions of women as contraceptives and in hormone replacement therapy (HRT), although their molecular mechanisms of action are not well understood. The importance of investigating these mechanisms, as compared to those of progesterone, has been highlighted by clinical evidence showing that medroxyprogesterone acetate (MPA), a first generation progestin, increases the risk of breast cancer and coronary heart disease in HRT users. A diverse range of later generation progestins with varying structures and pharmacological properties is available for therapeutic use and it is becoming clear that different progestins elicit beneficial and adverse effects to different extents. These differences in biological activity are likely to be due to many factors including variations in dose, metabolism, pharmacokinetics, bioavailability, and regulation of, and/or binding, to serum-binding proteins and steroidogenic enzymes. Since the intracellular effects on gene expression and cell signaling of steroids are mediated via intracellular steroid receptors, differential actions via the progesterone and other steroid receptors and their isoforms, are likely to be the major cause of differential intracellular actions of progestins. Since many progestins bind not only to the progesterone receptor, but also to the glucocorticoid, androgen, mineralocorticoid, and possibly the estrogen receptors, it is plausible that synthetic progestins exert therapeutic actions as well as side-effects via some of these receptors. Here we review the molecular mechanisms of intracellular actions of old (MPA, norethisterone, levonorgestrel, gestodene) vs. new (drospirenone, dienogest, trimegestone) generation progestins, via steroid receptors.

Different cardiovascular effects of progestins according to structure and activity.

Following the publication of the Women's Health Initiative study, the controversy was raised regarding the role of progestins in hormonal replacement therapy (HRT). Some of the most prescribed molecules, with partial androgenic or glucocorticoid activity, have been shown to oppose partially the beneficial effect of estrogens on surrogate markers of cardiovascular disease risk. Unfortunately, this concern has been directed towards progestins as a class effect, although striking differences exist among the types of molecules used. The synthetic progestins used in HRT have varying pharmacologic properties depending on the molecules from which they are derived, either testosterone or progesterone. Very small structural changes in these molecules may induce considerable difference in their effects on various targets and especially on the surrogate markers of cardiovascular disease risk, where some molecules may reverse the beneficial effects of estrogen. Natural progesterone and some of its derivatives such as the 19-norprogesterone molecules or the new molecules drospirenone, a potent antimineralocorticoid agent with a beneficial effect on blood pressure, and dienogest do not exert any androgenic effect and have no negative effect on the lipids or on the endothelial cells. Although it is likely that the new progestins may be neutral on the coronary disease risk, when administered to the younger postmenopausal woman, this has not as yet been documented by large, randomized, controlled trials.

Met909 plays a key role in the activation of the progesterone receptor and also in the high potency of 13-ethyl progestins.

Many progestins have been developed for use in contraception, menopausal hormone therapy, and treatment of gynecological diseases. They are derived from either progesterone or testosterone, and they act by binding to the progesterone receptor (PR), a hormone-inducible transcription factor belonging to the nuclear receptor superfamily. Unlike mineralocorticoid, glucocorticoid, and androgen receptors, the steroid-receptor contacts that trigger the switch of the ligand-binding domain from an inactive to an active conformation have not yet been identified for the PR. With this aim, we solved the crystal structure of the ligand-binding domain of the human PR complexed with levonorgestrel, a potent testosterone-derived progestin characterized by a 13-ethyl substituent. Via mutagenesis analysis and functional studies, we identified Met909 of the helix 12 as the key residue for PR activation by both testosterone- and progesterone-derived progestins with a 13-methyl or a 13-ethyl substituent. We also showed that Asn719 contributes to PR activation by testosterone-derived progestins only, and that Met759 and Met909 are responsible for the high potency of 19-norprogestins and of 13-ethyl progestins, respectively. Our findings provide a structural guideline for the rational synthesis of potent PR agonist and antagonist ligands that could have therapeutic uses in women's health.

Copper-catalyzed cyclization of steroidal acylaminoacetylenes: syntheses of novel 11beta-aryl-17,17- spiro[(4'H,5'-methylene)oxazol]-substituted steroids.

A variety of novel 11beta-aryl-17,17-spiro[(4'H,5'-methylene)oxazol]-substituted steroids have been synthesized in moderate to good yields via copper-catalyzed cyclization of acylaminoacetylenes. The best result was obtained with a catalytic amount of CuI in 1:1 benzene-Et3N at 90 degrees C for 30 min (Ar = 3,4-difluorophenyl; R = ethyl; 97% yield).

A full conformational characterization of 13-ethylprogestogens through theoretical calculations and nuclear magnetic resonance spectroscopy.

The conformational preferences of a group of 13-ethylsteroids and related estranes have been determined through theoretical calculations at the B3LYP/6-31G(*) level in order to ascertain differences and similarities in the conformational behavior which might, in principle, influence the activity. Attention was focussed on two geometrical features usually related to the progestational activity of this class of compounds, namely, the inversion of the A ring and the orientation of the 13-ethyl group. The present calculations show that the absence of the C10 methyl group, like in levonorgestrel, 3-ketodesogesterel, and gestodene, makes the inversion of the A ring easier than in norethisterone and ethisterone even if in any case the 1alpha,2beta-half-chair conformation remains preferred. The preference of the ethyl group for the trans orientation is maintained by all the 13-ethylprogestogens though in gestodene also the g(+)gauche conformation is significantly populated. This preference was experimentally supported through a high field NMR spectroscopy study of the ethylsteroids.

[Influence of the structure of synthetic gestagens on their binding to progesteron receptors in the endometrium].

Chemical modification of progesterone molecule leads to changes both in the gestagenic activity of new derivatives and in their specific binding with progesterone receptors. The passage from esters (acetomepregenole, butagest) to the corresponding OH-forms such as 17a-acetoxy-3b-hydroxy-6-methyl-pregna-4,6-dien-20-one (ABMP)is accompanied by an increase in the binding with progesterone receptors in vitro. The translocation of a double bond from endocyclic (N6-N7) to exocyclic position (methylene group at N6 in ABMP) has no significant effect on the ability to binding with progesterone receptors.

Not all progestins are the same: implications for usage.

Recent clinical evidence showing unexpected side-effects of progestins used in contraception and hormone replacement therapy has highlighted the importance of choice of synthetic progestin. The molecular mechanisms of action of the relatively nonspecific and most widely used synthetic progestins, medroxyprogesterone acetate and norethisterone, are discussed in the context of this recent clinical evidence. Future directions involving a more mechanism-based approach for improved therapeutics, with greater specificity and fewer side-effects, are discussed.