Serum levels of oestrogens, progesterone, follicle-stimulating hormone and sex-hormone-binding globulin during simultaneous vaginal administration of 17 beta-oestradiol and progesterone in the pre- and post-menopause

Advanced drug delivery technologies for postmenopausal effects

Postmenopause is the 12-month absence of menstrual periods, characterized by decreased estrogen and progesterone levels, leading to physical and psychological alterations such as hot flashes, mood swings, sleep disruptions, and skin changes. Present postmenopausal treatments include hormone replacement therapy, non-hormonal drugs, lifestyle modifications, vaginal estrogen therapy, bone health treatments, and alternative therapies. Advanced drug delivery systems (ADDSs) are essential in managing postmenopausal effects (PMEs), offering targeted and controlled delivery to alleviate symptoms and improve overall health. This review emphasizes such ADDSs for addressing PMEs. Emerging trends such as artificial ovaries are also reviewed. Additionally, the prospects of technologies such as additive manufacturing (3D and 4D printing) and artificial intelligence in further tailoring therapeutic strategies against PMEs are provided.

3D printing in vaginal drug delivery: a revolution in pharmaceutical manufacturing

INTRODUCTION

The Food and Drug Administration's approval of the first three-dimensional (3D) printed tablet, Spritam®, led to a burgeoning interest in using 3D printing to fabricate numerous drug delivery systems for different routes of administration. The high degree of manufacturing flexibility achieved through 3D printing facilitates the preparation of dosage forms with many actives with complex and tailored release profiles that can address individual patient needs.

AREAS COVERED

This comprehensive review provides an in-depth look into the several 3D printing technologies currently utilized in pharmaceutical research. Additionally, the review delves into vaginal anatomy and physiology, 3D-printed drug delivery systems for vaginal applications, the latest research studies, and the challenges of 3D printing technology and future possibilities.

EXPERT OPINION

3D printing technology can produce drug-delivery devices or implants optimized for vaginal applications, including vaginal rings, intra-vaginal inserts, or biodegradable microdevices loaded with drugs, all custom-tailored to deliver specific medications with controlled release profiles. However, though the potential of 3D printing in vaginal drug delivery is promising, there are still challenges and regulatory hurdles to overcome before these technologies can be widely adopted and approved for clinical use. Extensive research and testing are necessary to ensure safety, effectiveness, and biocompatibility.

A model for predicting low progesterone levels on the day of embryo transfer in hormonally prepared vitrified-warmed embryo transfer cycles: A secondary analysis of a prospective cohort study

AIM

To develop a model that predicts low progesterone (P) levels on the day of embryo transfer (ET) based on patient and cycle characteristics, including serum estradiol (E2 ) concentration after vaginal administration of micronized E2 for endometrial preparation.

METHODS

A prospective cohort of 193 patients scheduled for cryopreserved blastocyst transfer during an artificial endometrial preparation cycle, using micronized E2 vaginally for first 4 days (4 mg/day), followed by oral administration (6 mg/day). Blood sampling for E2 was performed prospectively on day-5 of vaginal administration and analysis was performed retrospectively. On sixth day of P treatment (daily 300 mg of vaginal micronized P tablets), P levels were measured on ET day. Primary outcome measure was serum P levels after vaginal E2 administration.

RESULTS

Patients with low P levels on the day of ET (<7.8 ng/mL, 25th percentile) were heavier (p < 0.001) and exhibited lower day 5 serum E2 levels (p < 0.001) compared with patients with adequate P levels. Multivariate linear regression analysis revealed that weight (p = 0.003) and day 5 E2 levels (p < 0.001) were independently associated with the P levels. The sensitivity, specificity, and positive and negative predictive values (%) were 71.4, 55.6, 35.4, and 85.1 for weight ≥ 65 kg; 71.4, 61.8, 38.9, and 86.4 for day 5 E2  ≤ 1615 pg/mL; 59.2, 83.3, 54.7, and 85.7 for the combination of these two variables; and 82.9, 62.5, 54.7, and 87.0 for the sequential inclusion of these variables, respectively.

CONCLUSIONS

Low day 5 E2 levels following vaginal administration and high weight are independently associated with low P levels on the day of ET. Predictive performance is enhanced when these variables are considered sequentially or in combination.

Advances and future perspectives in epithelial drug delivery

Epithelial surfaces protect exposed tissues in the body against intrusion of foreign materials, including xenobiotics, pollen and microbiota. The relative permeability of the various epithelia reflects their extent of exposure to the external environment and is in the ranking: intestinal≈ nasal ≥ bronchial ≥ tracheal > vaginal ≥ rectal > blood-perilymph barrier (otic), corneal > buccal > skin. Each epithelium also varies in their morphology, biochemistry, physiology, immunology and external fluid in line with their function. Each epithelium is also used as drug delivery sites to treat local conditions and, in some cases, for systemic delivery. The associated delivery systems have had to evolve to enable the delivery of larger drugs and biologicals, such as peptides, proteins, antibodies and biologicals and now include a range of physical, chemical, electrical, light, sound and other enhancement technologies. In addition, the quality-by-design approach to product regulation and the growth of generic products have also fostered advancement in epithelial drug delivery systems.

The role of combining medroxyprogesterone 17-acetate with human menopausal gonadotropin in mouse ovarian follicular development

Medroxyprogesterone 17-acetate (MPA) combined with human menopausal gonadotropin (hMG) has been effectively used for ovarian stimulation in clinical practice. However, the molecular mechanism of MPA + hMG treatment in follicular development is poorly described. Here we performed a study to investigate the impact of MPA + hMG on ovarian stimulation utilizing a mouse model in vivo. Forty female BALB/C mice were randomly divided into four groups of 10 each and treated during ciestrus stage and continued for 5 days: control group, MPA group, hMG group, and MPA + hMG group. Morphological and molecular biology methods were used for detecting serum hormones and ovarian function. MPA + hMG group exhibited increasing follicle stimulating hormone (FSH), antral follicle, FSH receptor (FSHR) and phosphorylated mammal target of rapamycin (p-mTOR), and decreasing luteinizing hormone (LH), estradiol (E2), progesterone (P), corpus luteum, phosphoinositide 3-kinase (PI3K), Akt and mTOR compared with control group. In contrast, MPA + hMG group showed reduced FSH, LH, E2, P, corpus luteum, LH receptor (LHR), and activated PI3K,/Akt/mTOR pathway compared with hMG group (P < 0.05). Collectively, these data definitively established that MPA plus hMG may modulate the hormone, hormone receptor and PI3K/Akt/mTOR signaling pathway to influence follicular development in the mouse ovary. Our study provides overwhelming support for MPA + hMG as an effective treatment for infertility in women.

Studies and methodologies on vaginal drug permeation

The vagina stands as an important alternative to the oral route for those systemic drugs that are poorly absorbed orally or are rapidly metabolized by the liver. Drug permeation through the vaginal tissue can be estimated by using in vitro, ex vivo and in vivo models. The latter ones, although more realistic, assume ethical and biological limitations due to animal handling. Therefore, in vitro and ex vivo models have been developed to predict drug absorption through the vagina while allowing for simultaneous toxicity and pathogenesis studies. This review focuses on available methodologies to study vaginal drug permeation discussing their advantages and drawbacks. The technical complexity, costs and the ethical issues of an available model, along with its accuracy and reproducibility will determine if it is valid and applicable. Therefore every model shall be evaluated, validated and standardized in order to allow for extrapolations and results presumption, and so improving vaginal drug research and stressing its benefits.

The vagina as a route for drug delivery: a review

Overactive bladder (OAB) syndrome has a significant deleterious impact on quality of life. After conservative therapy and bladder retaining, antimuscarinic drugs remain the mainstay of OAB management. Oral therapy is associated with frequent side effects, leading to the development of alternative agents and formulations or the use of novel routes of drug administration, such as the vaginal route. The vagina is often ideal for drug delivery because it allows the use of lower doses, maintains steady drug administration levels, and requires less frequent administration than the oral route. With vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet. The aim of this review is to provide a background overview of vaginal development, anatomy, and physiology and the effect this has on the use of this route for both local and systemic drug delivery, with special reference to OAB management. Vaginal therapy continues to be an underused route of drug delivery. Vaginal administration allows nondaily, low, continuous dosing, which results in stable drug levels and may, in turn, achieve a lower incidence of side effects and improve patient compliance. These benefits must be balanced against inherent patient or physician bias against using this route and the need to overcome cultural, personal, and hygiene-related barriers to this form of therapy. More sophisticated and programmable vaginal rings are being developed for systemic delivery of therapeutically important macromolecules, such as antimuscarinic therapy in OAB management.

The vagina as a route for systemic drug delivery

Exhaustive efforts have been made toward the administration of drugs, via alternative routes, that are poorly absorbed after the oral administration. The vagina as a route of drug delivery has been known since ancient times. In recent years, the vaginal route has been rediscovered as a potential route for systemic delivery of peptides and other therapeutically important macromolecules. However, successful delivery of drugs through the vagina remains a challenge, primarily due to the poor absorption across the vaginal epithelium. The rate and extent of drug absorption after intravaginal administration may vary depending on formulation factors, vaginal physiology, age of the patient and menstrual cycle. Suppositories, creams, gels, tablets and vaginal rings are commonly used vaginal drug delivery systems. The purpose of this communication is to provide the reader with a summary of advances made in the field of vaginal drug delivery. This report, therefore, summarizes various vaginal drug delivery systems with an introduction to vaginal physiology and factors affecting drug absorption from the vaginal route.

Wellness in women after 40 years of age: the role of sex hormones and pheromones

In the past twenty years hundreds of peer-reviewed studies have provided a significant body of information to guide the health care of women in the second halves of their lives. The harmonic nature of the fertile reproductive system forms the background against which hormonal replacement therapy can be understood to best serve women. In addition, the 1986 discovery of human pheromones and the subsequent 1998 confirmation of their existence increases certain sexual options for maturing women. Not all hormonal replacement therapies and wellness regimens serve women well. Some regimens have the potential to produce disease, especially over-the-counter remedies like dehydroepiandrosterone and the formulas that contain estrogen. Some regimens profoundly improve the quality of life of many women; some women do not need or want such regimens. All sex hormones affect physiologic systems including the cardiovascular system, bone metabolism, cognitive function, sexual response, and sexual attractiveness. The 7 years before menopause have recently been revealed to be an extremely complex era. During this period, some women increase their estrogen levels to new lifetime highs; others start an unequivocal decline, and still others vary from month to month. Coupled to this variability in estrogen is an equally variable set of changes in progesterone secretion by the ovary as androgen secretion patterns also change. Many women show increases in circulating androgens while many others show deficiencies. Both the adrenal and the ovarian sources of these hormones show age-related changes that alter a woman's capacity to attract sexual attention through both her physical appearance (and condition) and her pheromonal excretions. The complex contributions to the overall health of a woman may not always be understood. Often a hysterectomy can exacerbate--rather than ameliorate--the conditions that led to the surgery. One in 2 American women is offered a hysterectomy, a rate 5 times higher than that of the European countries for which data are available. Ninety percent of hysterectomies are not related to cancer; they are elective procedures. Avoidance of elective hysterectomy helps prevent its side effects: sexual deficits, acceleration of cardiovascular and bone disease, and more rapid aging. No efficacy data exist that suggest that elective hysterectomy works better than the alternative approaches that do not induce these side effects. The health and well-being of women who have already had hysterectomies, with or without ovariectomies, can be improved by a recognition of the cascade of difficulties that must addressed. Estrogen, progesterone, and androgens all tend to be compromised by hysterectomy; all should be considered for replacement. Because hormonal regimens can be prescribed to enhance the quality of life, the review of the available research can allow the medical art to greatly benefit mature women. Not surprisingly, the emerging conclusion reveals that structurally human hormones, prescribed appropriately, almost always best serve the patient.

A morphologist's approach to the vagina--age-related changes and estrogen sensitivity

This paper reviews basic facts on vagina histology and ultrastructure with respect to passage of different substances and drugs through the epithelium. Particular interest is devoted to the action mechanism of topically-applied vaginal estrogen, its binding to receptors in different vaginal cell types, and possible local metabolic routes. Differences in estrogen sensitivity between uterus and vagina are discussed as well as the background for the high vaginal sensitivity.

Profiles of plasma estrogens, progesterone and their metabolites after oral or vaginal administration of estradiol or progesterone

Doses of 100 mg of micronized progesterone (P) and of 0.5 mg of micronized estradiol (E2) were administered vaginally and orally, respectively, in the early follicular phase of the menstrual cycle in six premenopausal women. In the second cycle, the same doses were administered in the same subjects, orally for P and vaginally for E2. Serial blood samples were collected and the following steroids were assayed by highly reliable techniques: P, E2, estrone (E1), deoxycorticosterone (DOC), 5 alpha- and 5 beta-pregnanolone and the sulfates of E1, E2, and DOC. Circulating P and E2 levels were higher after vaginal than after oral administration, while those of E1 were similar after either route. Metabolites of P (DOC, DOCS and pregnanolone) were higher after oral administration. Concerning estrogen sulfates, E1S concentrations were similar whichever the route, while those of E2S were lower after oral than after vaginal administration. This study has confirmed that metabolism of ingested P and E2 occurs mainly in the intestine. Moreover, P was predominantly metabolized to 5 alpha-reduced derivatives, whatever the route of administration. In view of the metabolic pathways which are operative and of the peripheral plasma levels which were found, the vaginal route appears to be more adequate than the oral one for hormone replacement therapy.