Danazol concentrations in ovary, uterus, and serum and their effect on the hypothalamic-pituitary-ovarian axis during vaginal administration of a danazol suppository

Novel drug delivery methods for improving efficacy of endometriosis treatments

INTRODUCTION

Pharmacotherapy has a key role in the management of endometriosis. However, a significant proportion of patients gains only intermittent or limited benefits. In this regard, alternative and novel drug delivery methods are of paramount importance to improve efficacy and compliance of available treatments and develop alternative medical approaches.

AREAS COVERED

This review aims to provide the reader with a complete overview of available evidence about alternative and novel drug delivery methods for endometriosis pharmacotherapy and highlight new research lines.

EXPERT OPINION

Progestins and estroprogestins, which represent the first-line therapy, are already available in different formulations, being employed for contraception. Nevertheless, evidence on their adoption is still limited for some drug delivery methods, such as vaginal rings, patches, and subcutaneous implants. Further research is needed to define better their clinical utility in patients with endometriosis. Nanotechnologies have been investigated as novel drug delivery methods able to target the drug at the disease level. However, data are very limited and preliminary, and further research is needed to consider a possible clinical application in endometriosis.

Endometriosis Pain Management: a Review

PURPOSE OF REVIEW

The purpose of this review is to summarize the up-to-date pain management options and recommendations for the challenging disease, endometriosis.

RECENT FINDINGS

The mainstays of endometriosis advances of both surgical and medical management continue to evolve. Experimental pharmaceuticals include Gestirone, and aromatase inhibitors have shown promise but are still under scrutiny. Surgical techniques include laparoscopic uterosacral nerve ablation/resection and presacral neurectomy. No studies have directly compared medical versus surgical management, and as such, no one treatment modality can be recommend as superior to the other. Patients may initially be given a medical diagnosis and treated with nonsteroidal anti-inflammatory drugs, neurolepitcs, OCP, GNRH agonists/antagonists, and Danazol. Assessing the success of these regimens has proved difficult. Surgical management relies on various methods including excision/ablation of the lesions, nerve ablation, neurectomy, hysterectomy, and oophorectomy.

Progesterone receptor ligands for the treatment of endometriosis: the mechanisms behind therapeutic success and failure

BACKGROUND

Despite intense research, it remains intriguing why hormonal therapies in general and progestins in particular sometimes fail in endometriosis.

OBJECTIVE AND RATIONALE

We review here the action mechanisms of progesterone receptor ligands in endometriosis, identify critical differences between the effects of progestins on normal endometrium and endometriosis and envisage pathways to escape drug resistance and improve the therapeutic response of endometriotic lesions to such treatments.

SEARCH METHODS

We performed a systematic Pubmed search covering articles published since 1958 about the use of progestins, estro-progestins and selective progesterone receptor modulators, to treat endometriosis and its related symptoms. Two reviewers screened the titles and abstracts to select articles for full-text assessment.

OUTCOMES

Progesterone receptor signalling leads to down-regulation of estrogen receptors and restrains local estradiol production through interference with aromatase and 17 beta-hydroxysteroid dehydrogenase type 1. Progestins inhibit cell proliferation, inflammation, neovascularisation and neurogenesis in endometriosis. However, progesterone receptor expression is reduced and disrupted in endometriotic lesions, with predominance of the less active isoform (PRA) over the full-length, active isoform (PRB), due to epigenetic abnormalities affecting the PGR gene transcription. Oxidative stress is another mechanism involved in progesterone resistance in endometriosis. Among the molecular targets of progesterone in the normal endometrium that resist progestin action in endometriotic cells are the nuclear transcription factor FOXO1, matrix metalloproteinases, the transmembrane gap junction protein connexin 43 and paracrine regulators of estradiol metabolism. Compared to other phenotypes, deep endometriosis appears to be more resistant to size regression upon medical treatments. Individual genetic characteristics can affect the bioavailability and pharmacodynamics of hormonal drugs used to treat endometriosis and, hence, explain part of the variability in the therapeutic response.

WIDER IMPLICATIONS

Medical treatment of endometriosis needs urgent innovation, which should start by deeper understanding of the disease core features and diverse phenotypes and idiosyncrasies, while moving from pure hormonal treatments to drug combinations or novel molecules capable of restoring the various homeostatic mechanisms disrupted by endometriotic lesions.

Optimization of a Vaginal Suppository Formulation to Deliver SHetA2 as a Novel Treatment for Cervical Dysplasia

Cervical dysplasia induced by the human papilloma virus unpredictably progresses to cervical cancer. Therapeutic options are invasive and affect the patient's quality of life. SHetA2 has demonstrated therapeutic efficacy against human and murine human papilloma virus-induced tumors, but its oral bioavailability is <1%. An optimized vaginal suppository formulation can deliver SHetA2 in sufficient doses to prevent cervical dysplasia. The quality by design approach was employed to optimize the suppository formulation consisting of cocoa butter as base with 5% Kolliphor and 40% SHetA2. The suppository had a content uniformity of 105.44 ± 0.42%, melted in <8 min, and had a complete release of SHetA2 in water. Administration of the suppository to mice-achieved cervix concentrations that were significantly higher than the SHetA2 therapeutic concentration, with the maximum concentration (C_max-cervix = 336.78 μg/g) being more than 100-fold the therapeutic SHetA2 concentration. Furthermore, the levels of cyclin D1 protein decreased 9-fold indicating a correlation of drug concentrations with the pharmacodynamic endpoint. These proof-of-concept studies suggest that the SHetA2 optimized vaginal suppository formulation may have a potential use in the prevention of cervical dysplasia, but detailed efficacy studies are required to confirm this assumption.

"Per vaginam" topical use of hormonal drugs in women with symptomatic deep endometriosis: a narrative literature review

PURPOSE

We aim to provide a comprehensive overview of the role of the vagina as a route for drug delivery and absorption, with a particular focus on the use of vaginal hormonal compounds for the treatment of deep infiltrating symptomatic endometriosis.

METHODS

A MEDLINE search through PubMed was performed to identify all published studies in English language on vaginal hormonal treatments for symptomatic endometriosis.

RESULTS

Main advantages of the vaginal route include avoidance of the hepatic-first pass metabolic effect, the possibility of using lower therapeutic dosages, and the reduction of side effects compared with the oral administration. Studies on endometriosis treatment mainly focused on the use of vaginal danazol (n = 6) and the contraceptive vaginal ring (n = 2). One pilot study evaluated the efficacy of vaginal anastrozole in women with rectovaginal endometriosis. Most investigations evaluated the vaginal use of hormonal agents in women with deep infiltrating endometriosis/rectovaginal endometriosis. Overall, a substantial amelioration of pelvic pain symptoms associated with endometriosis was observed, particularly of dysmenorrhea. A significant reduction in rectovaginal endometriotic nodule dimensions measured at ultrasound examination was detected by some but not all authors.

CONCLUSIONS

The vaginal route represents a scarcely explored modality for drug administration. High local hormonal concentrations might achieve a greater effect on endometriotic lesions compared with alternative routes. Future studies should focus on the use of the vagina for delivering target therapies particularly in patients with deeply infiltrating rectovaginal lesions.

Long-Term Vaginal Danazol Treatment in Fertile Age Women with Adenomyosis

Background

The aim of the study was to evaluate the clinical efficacy of long-term vaginal danazol treatment in fertile age women with adenomyosis on pain symptoms and abnormal uterine bleeding (AUB).

Methods

A retrospective study on 66 young women with dysmenorrhea and/or dyspareunia, AUB and 2D-ultrasound diagnosis of adenomyosis was conducted at University Hospital of Siena (Italy). Women included were treated with a daily low-dose vaginal danazol (200 mg) for 6 months, followed by 2 different schedules: group A) continuous treatment for further 18 months (n = 30); group B) cyclic intermittent treatment with 3 months’ therapy followed by 3 months’ interval for further 18 months (n = 36). A visual analog scale (VAS) for pain symptoms, a pictorial blood-loss assessment chart (PBAC) for uterine bleeding, 2D-ultrasound signs of adenomyosis and quality-of-life measures were assessed at baseline and after both vaginal progestin regimens.

Results

The pain symptoms, PBAC score and uterine volume were significantly reduced (p<0.0001) after 6 months, and the reduction persisted in both group of patients until the end. Mental and physical index score values increased (p<0.0001) in both groups at the end of treatment, with significantly higher mental index scores in intermittent than in continuous treatment (p<0.0001), associated with some drop-out (10%).

Conclusions

A long-term treatment with vaginal danazol is effective to control pain and AUB in women with adenomyosis. The 6 months’ treatment followed by a cyclic 3 months’ treatment for further 18 months has the best compliance in symptomatic patients with adenomyosis.

Current and Future Medical Treatment of Adenomyosis

Adenomyosis is a benign gynecological disorder associated with abnormal uterine bleeding, dysmenorrhea, dyspareunia and infertility, requiring a life-long management plan through medical or surgical treatment. The choice depends on woman's age, reproductive status and clinical symptoms. However, until now no drug labelled for adenomyosis is available; thus, the present review will focus on medical treatments currently used for adenomyosis and those in development.

Adenomyosis may be considered a sex steroid hormone-related disorder associated with an intense inflammatory process. The use of gonadotropin-releasing hormone agonists (GnRH-a) for treating adenomyosis is described blocking the hypothalamic-pituitary-gonadal axis; however, it has long been associated with frequent and intolerable hypoestrogenic side effects. An antiproliferative effect of progestins suggests their use for treating adenomyosis, reducing bleeding and pain. Continuous oral norethisterone acetate or medroxyprogesterone acetate may help to inducing regression of adenomyosis, relief pain and reduce bleeding. The use of vaginal danazol has therapeutic effect on adenomyosis combining progestogenic and anti-inflammatory activity. The intrauterine device releasing levonorgestrel (Lng-IUD) is widely assessed in menorrhagia, and has been shown to be extremely effective in resolving pain and bleeding symptoms associated with adenomyosis. Recent data show a therapeutic effect of dienogest on adenomyosis symptoms.

New drugs are under development for the treatment of adenomyosis, such as aromatase inhibitors (AIs) and selective estrogen receptor modulators (SERMs), that produce a hypoestrogenic environment reducing pain, but are correlated with some adverse effects and a recurrence of symptoms after discontinuation of treatment. Selective progesterone receptor modulators (SPRMs) may reduce adenomyosis-associated pelvic pain, by inhibiting endometrial proliferation and suppressing adenomyotic lesion growth, as shown in animal models; however, the long-term effect with SPRMs needs further determination.

Clinical trial considerations on male contraception and collection of pregnancy information from female partner: update

BACKGROUND

This is an update to our 2012 publication on clinical trial considerations on male contraception and collection of pregnancy information from female partner, after critical review of recent (draft) guidances released by the International Council for Harmonisation [ICH] the Clinical Trial Facilitation Group [CTFG] and the US Food & Drug Administration [FDA].

METHODS

Relevant aspects of the new guidance documents are discussed in the context of male contraception and pregnancy reporting from female partner in clinical trials and the approach is updated accordingly.

RESULTS

Genotoxicity The concept of a threshold is introduced using acceptable daily intake/permissible daily exposure to define genotoxicity requirements, hence highly effective contraception in order to avoid conception. The duration for highly effective contraception has been extended from 74 to 90 days from the end of relevant systemic exposure. Teratogenicity Pharmacokinetic considerations to estimate safety margins have been contextualized with regard to over- and underestimation of the risk of teratogenicity transmitted by a vaginal dose. The duration of male contraception after the last dose takes into account the end of relevant systemic exposure if measured, or a default period of five half-lives after last dose for small molecules and two half-lives for immunoglobulins (mAbs). Measures to prevent exposure of the conceptus via a vaginal dose apply to reproductively competent or vasectomized men, unless measurements fail to detect the compound in seminal fluid.

CONCLUSION

Critical review of new guidance documents provides a comparison across approaches and resulted in an update of our previous publication. Separate algorithms for small molecules and monoclonal antibodies are proposed to guide the recommendations for contraception for male trial participants and pregnancy reporting from female partners. No male contraception is required if the dose is below a defined threshold for genotoxic concern applicable to small molecules. For men treated with teratogenic mAbs, condom use to prevent exposure of a potentially pregnant partner is unlikely to be recommended because of the minimal female exposure anticipated following a vaginal dose. The proposed safety margins for teratogenicity may evolve with further knowledge.

Treatment of pelvic pain associated with endometriosis: a committee opinion

Pain associated with endometriosis may involve many mechanisms and requires careful evaluation to confirm the diagnosis and exclude other potential causes. Both medical and surgical treatments for pain related to endometriosis are effective, and choice of treatment must be individualized. This document replaces the document by the same name last published in 2008 (Fertil Steril 2008;90:S260-9).

The practicability and surgeons' subjective experiences with vaginal danazol before an operative hysteroscopy

This randomized, double blind, placebo-controlled study compared the usefulness of danazol 400mg vaginally versus 600mg orally in women as a preoperative preparation for hysteroscopic surgery. Ninety-one fertile women were randomly allocated to Group A (46 patients received 400mg of danazol placed into the posterior vaginal fornix and three oral tablets of commercially available folic acid as a placebo), and Group B [45 women treated with 600mg of danazol orally (200mg three times daily) and two vaginal tablets of Lactobacillus rhamnosus as a placebo]. The patients underwent an operative hysteroscopy, transvaginal sonography, blood tests, and a histological assay. A visual analog scale (VAS) score to compute the degree of the surgeon's satisfaction was used. The outcome measures were as follows: an evaluation of the changes in the endometrial thickness, the prevalence of endometrial atrophy, changes in the blood tests, any collateral effects, the degree of difficulty and view, the duration of the surgical procedure, any complications during the operative hysteroscopy and associated side effects, and the surgeon's satisfaction with the endometrial preparation. The vaginal administration route was associated with a more pronounced effect on the endometrial thickness. Significantly more patients receiving vaginal danazol (45/46) had a hypotrophic endometrium than those receiving oral danazol (37/45, P<0.01). In addition, the patients receiving danazol vaginally had a shorter operating time, lower infusion volume, fewer side effects, and a higher surgeon satisfaction. Vaginal danazol adequately prepares the endometrium for an operative hysteroscopy by thinning the endometrium effectively with few side effects and little impact on the metabolic parameters.

New treatment strategies and emerging drugs in endometriosis

Introduction: Endometriosis, histologically defined as the presence of endometrium-like tissue - glands and stroma - that develops outside of the uterine cavity, is still an enigmatic disease responsible for pelvic pain and infertility. The current treatments of endometriosis are surgery and hormonal therapies that act by suppressing ovulation and/or directly on steroid receptors located in endometriotic lesions. Areas covered: New hormonal and non-hormonal therapies are being developed for the treatment of endometriosis-related pain. The authors review the state of advancement and the results of novel treatments studied in registered trials ( www.ClinicalTrials.gov ). Cellular signaling pathways activated in endometriotic cells, which constitute potential targets for future treatments, are also described. Expert opinion: Therapeutic research efforts should focus on identifying and testing substances capable of acting locally on the lesions themselves, without interfering with ovulation, in order to be efficacious on both pain symptoms and infertility.

Markers of adult endometriosis detectable in adolescence

Endometriosis, a disease of young females that is possibly a devastating ailment requiring surgery, appears to be associated with certain features encountered in adolescence. First among these symptoms is the history of severe and lasting dysmenorrhea at the time of adolescence and the need to use oral contraceptives (OCs) for alleviating dysmenorrhea that failed to respond to nonsteroidal anti-inflammatory drugs (NSAIDs). Further awareness about existing associations between certain symptoms experienced at adolescence and the later development of endometriosis is important. Indeed, the possibility of diagnosing endometriosis earlier when suggested by clinical history could lead to less extensive surgery and thus, less damage. Experimental verification of this insight, however, is needed before the concept that early diagnosis means lesser destructive surgery can be ascertained.

Medical treatment for rectovaginal endometriosis: what is the evidence?

BACKGROUND

Rectovaginal endometriosis usually causes distressing pain. Surgical treatment may be effective but is associated with a high risk of morbidity and major complications. Information on the effect of medical alternatives for pain relief in this condition is scarce.

METHODS

A comprehensive literature search was conducted to identify all the English language published observational and randomized studies evaluating the efficacy of medical treatments on pain associated with rectovaginal endometriosis. A combination of keywords was used to identify relevant citations in PubMed, MEDLINE and EMBASE.

RESULTS

A total of 217 cases of medically treated rectovaginal endometriosis were found; 68 in five observational, non-comparative studies, 59 in one patient preference cohort study, and 90 in a randomized controlled trial. An aromatase inhibitor was used in two of the non-comparative studies, vaginal danazol in one, a GnRH agonist in one, and an intrauterine progestin in one. Two estrogen-progestin combinations used transvaginally or transdermally were evaluated in the patient preference study, whereas an oral progestin and an estrogen-progestin combination were compared in the randomized controlled trial. With the exception of an aromatase inhibitor used alone, the antalgic effect of the considered medical therapies was high for the entire treatment period (from 6 to 12 months), with 60-90% of patients reporting considerable reduction or complete relief from pain symptoms.

CONCLUSIONS

Despite problems in interpretation of data, the effect of medical treatment in terms of pain relief in women with rectovaginal endometriosis appear substantial.

Hormone therapy for endometriosis and surgical menopause

BACKGROUND

Endometriosis is characterized by the presence of ectopic endometrial tissue that might lead to many distressing and debilitating symptoms. Despite available studies supporting standard hormone therapy for women with endometriosis and post-surgical menopause, there is still a concern that estrogens may induce a recurrence of the disease and its symptoms.

OBJECTIVES

This review aimed to look at pain and disease recurrence in women with endometriosis who used hormone therapy for post-surgical menopause.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group Specialized Register (March 2008), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 3), MEDLINE (1966 to March 2008), EMBASE (1980 to March 2008), and references lists of articles. Relevant journals and conference proceedings were handsearched.

SELECTION CRITERIA

Randomized controlled trials studying hormone therapy for women with endometriosis in post-surgical menopause.

DATA COLLECTION AND ANALYSIS

Review authors assessed the eligibility of trials and their quality.

MAIN RESULTS

Two studies fulfilled our inclusion criteria. One trial compared the nonstop transdermal application of 17beta-estradiol (0.05 mg/day) combined with cyclic medroxy progesterone acetate (10 mg per day) for 12 days per month in women with a conserved uterus with nonstop tibolone (2.5 mg/day). The second trial used sequential administration of estrogens and progesterone with two 22 cm(2) patches applied weekly to produce a controlled release of 0.05 mg/day. Micronized progesterone was administered orally (200 mg/day) for 14 days with a 16-day interval free of treatment. Pain and dyspareunia The first trial reported recurrence of pain in the estrogen and progesterone arm in 4/10 of women compared with 1/11 in the tibilone arm. In the latter, 4/115 women reported recurrence of pain in the treatment group compared with 0/57 patients in the no-treatment arm. Neither finding was statistically different.Confirmed recurrence or exacerbation of endometriosis This outcome was not reported in the first trial. The second found that 2/115 of the treatment group developed recurrence of endometriosis with no recurrence reported in the no-treatment group. This was not statistically significant. No woman was re-operated on in the no-treatment group compared with 2/115 in the treatment group.

AUTHORS' CONCLUSIONS

Hormone replacement therapy for women with endometriosis in post-surgical menopause could result in pain and disease recurrence. However, the evidence in the literature is not strong enough to suggest depriving severely symptomatic patients from this treatment. There is a need for more randomised controlled studies.

Treatment of pelvic pain associated with endometriosis

Pain associated with endometriosis requires careful evaluation to exclude other potential causes and may involve a number of different mechanisms. Both medical and surgical treatments for pain related to endometriosis are effective and choice of treatment must be individualized.

Treatment of pelvic pain associated with endometriosis

Pain associated with endometriosis requires careful evaluation to exclude other potential causes and may involve a number of different mechanisms. Both medical and surgical treatments for pain related to endometriosis are effective and choice of treatment must be individualized.

Decreased suppression of interleukin-6 after treatment with medroxyprogesterone acetate and danazol in endometrial stromal cells of women with adenomyosis

OBJECTIVE

To examine changes in local cytokine production in the eutopic endometrium of adenomyosis after treatment with medroxyprogesterone acetate (MPA) and danazol.

DESIGN

Prospective cohort study.

SETTING

Tertiary university hospital.

PATIENT(S)

Twenty-four women with adenomyosis (study group) and 22 women without adenomyosis (control group).

INTERVENTION(S)

Eutopic endometrium was separated into single endometrial stromal cells (ESCs), and was cultured in vitro alone, with MPA (10(-7) M), or with danazol (10(-7) M) for 8 days.

MAIN OUTCOME MEASURE(S)

Messenger RNA expression of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha in ESCs, and their concentrations in the supernatants of ESCs.

RESULT(S)

A significant decrease of IL-6 concentration in the supernatant, measured by ELISA, was found with time of ESCs cultured with MPA and danazol in the control group, but not in adenomyosis. The IL-6 mRNA in ESCs determined by real-time quantitative polymerase chain, as well as its concentration in the supernatant, was much higher in adenomyosis than that in the control group after treatment with MPA and danazol for 8 days.

CONCLUSION(S)

Medroxyprogesterone acetate and danazol appeared to have a decreased effect on the suppression of IL-6 liberated by ESCs in adenomyosis. This aberrant secretion of IL-6 might play a role in the formation of ectopic endometrial implants in adenomyosis.

Influence of vaginal danazol on uterine and brain perfusion during hormonal replacement therapy

OBJECTIVE

To evaluate the effectiveness of vaginal danazol as progestin supplement to estrogen replacement therapy, and its interference with uterine and carotid artery flow compared with medroxyprogesterone-acetate (MPA), estrogen alone, and placebo.

METHODS

Forty healthy women at least 12 months after natural menopause were randomly divided into four treatment groups: Group 1 (n=10), continuous transdermal estradiol (TE) (50 microg/day), plus a monthly 10-day course of MPA (10 mg/day); Group 2 (n=10), continuous TE plus a monthly 10-day course of vaginal danazol (200 mg/day); Group 3 (n=10), TE alone; Group 4 (n=10), placebo. At baseline and during the first, third, and sixth month of treatment, the endometrial thickness was assessed by transvaginal ultrasonography, while the pulsatility index (PI) of the carotid and uterine arteries was assessed by color Doppler. An endometrial biopsy was also performed before and after the treatment.

RESULTS

At baseline, no significant differences between ages and other evaluated parameters were present in the four groups. In groups 1, 2, and 3, the values of carotid and uterine PI decreased significantly and similarly during the treatment, while in group 4 they were unchanged. In group 3 only, the endometrium was significantly thicker during treatment than before. No endometrial hyperplasia was present in the four groups at the end of the treatment.

CONCLUSIONS

Vaginal danazol seems to be capable of counteracting the mitogenic effect of estrogen on the endometrium without reducing the effectiveness of estrogens to improve peripheral arterial perfusion.

Danazol mimics antigestagen action in first trimester termination of pregnancy

BACKGROUND

Based on steroid receptor binding and biologic activity, danazol was suspected to be an antigestagen.

OBJECTIVE

To compare with placebo test in first trimester termination of pregnancy (TOP) as a method for predilatation of the cervix prior to application of misoprostol.

METHODS

52 patients were randomised into two groups. Thereby, 26 women received 200 mg danazol vaginal suppositories three times during 2 days before administering 200 microg misoprostol and undergoing mechanical dilatation and vacuum aspiration 5h later. The other 26 received placebo suppositories and the same treatment otherwise.

RESULT

The uterine cervix was wider and less dilatation and time was needed for the surgical termination in the group pretreated with danazol. There were six cases of complete abortion within 5h of administering misoprostol in the danazol group; and none in the placebo group. After danazol treatment, 16 women exhibited signs of abortion versus four receiving the inert suppositories.

CONCLUSION

Pretreatment with 200mg danazol suppositories three times starting 36 h before administering misoprostol for cervical dilatation enhances the effect of prostaglandin on cervical dilatation and uterine contractions in a manner similar to antigestagens.

Uterine contractility: vaginal administration of the beta-adrenergic agonist, terbutaline. Evidence of direct vagina-to-uterus transport

Spontaneous uterine contractility during the menstrual cycle is required for menstruation, gamete transport, and, most likely, embryo nidation. Abnormal uterine contractility has been linked to dysmenorrhea, a condition associated with painful uterine cramping. Based on previous studies with progesterone, we have postulated the existence of a portal system that is responsible for some degree of direct vagina-to-uterus transport of administered compounds (i.e., the "first uterine pass effect"). It is possible that treatment with uterorelaxing substances, particularly beta-adrenergic agonists, may alleviate the uterine discomfort that accompanies dysmenorrhea. However, side effects encountered with oral administration of beta-agonists limit their utility. Alternatively, vaginal delivery of beta-agonists could solve this dilemma by enhancing their efficacy and reducing side effects. Therefore, in the current study we used hysterectomy specimens and an in vitro uterine perfusion system to test the vagina-to-uterus transport of [3H]terbutaline, a well-known beta-agonist. With the use of autoradiographic and scintillation counting techniques, our results clearly show progressive diffusion of labeled terbutaline from the rim of vaginal tissue through the uterus during the first 12 hours of perfusion. This indicates that uterine targeting of terbutaline can be accomplished through vaginal administration, suggesting a new therapeutic modality in women's health care.

Comparison of the pharmacokinetics of crinone 8% administered vaginally versus Prometrium administered orally in postmenopausal women(3)

OBJECTIVE

Compare the pharmacokinetics of vaginal progesterone gel (Crinone 8%, 90 mg) with that of oral progesterone (Prometrium, 100 mg).

DESIGN

Open-label, randomized, parallel-group protocol.

SETTING

Outpatient clinic.

PATIENT(S)

Twelve healthy postmenopausal women.

INTERVENTION(S)

Six subjects each were randomized to receive progesterone, which was administered either as 90 mg of progesterone gel (Crinone 8%) given vaginally or 100 mg progesterone in a capsule (Prometrium) given orally.

MAIN OUTCOME MEASUREMENT(S)

Serum progesterone levels were measured by both radioimmunoassay (RIA) and liquid chromatography-mass spectrometry (LC-MS).

RESULT(S)

Progesterone given vaginally resulted in greater bioavailability with less relative variability in absorption than oral progesterone (mean AUC(0-24) = 1.48 +/- 0.16 ng. h/mL per milligram vs. 0.035 +/- 0.0052 ng. h/mL per milligram). Mean C(max) for oral progesterone was much lower than that of vaginal progesterone (i.e., 2.20 +/- 3. 06 ng/mL vs. 10.51 +/- 0.46 ng/mL). Mean T(max) occurred earlier for oral progesterone than for Crinone (1.00 +/- 0.41 hours vs. 7.67 +/- 3.67 hours). Radioimmunoassay is inappropriate for determining serum progesterone levels after oral administration, because it provided erroneously high values that were approximately eightfold higher than those obtained with LC-MS.

CONCLUSION(S)

Crinone (progesterone gel) given vaginally results in greater bioavailability with less relative variability than oral progesterone, thus providing more reliable delivery of progesterone, compared with oral progesterone. Measuring circulating progesterone with use of direct RIA is not appropriate after oral progesterone administration.

The first uterine pass effect

The endometrial effects of vaginal progesterone have been found to be unexpectedly reliable. This has led us to suspect that a local direct vagina-to-uterus transport or first uterine pass effect was the basis of the uterine targeting of vaginal progesterone. After vaginal administration of progesterone, uterine tissue concentration has been found to exceed by more than 10-fold the levels achieved by systemic administration, despite plasma levels in the latter case that were more than seven times higher. Similar differences in systemic-to-uterine tissue level ratios have been observed between oral and vaginal administration of danazol. Originally seen as a pharmacological advantage permitting the uterine targeting of vaginally administered substances, it is possible that the first uterine pass effect plays a physiological role in the control of uterine contractile activity through the prostaglandins contained in the semen.