In vivo assessment of NuvaRing® placement

Advances in contraception: vaginal contraceptive rings

The vaginal contraceptive ring is very effective and user dependent. In this article, we will discuss the different types of vaginal contraceptive rings, namely, the etonogestrel/ethinyl estradiol (ENG/EE) ring (NuvaRing, Merck, Rahway, NJ, USA) and the segesterone acetate (SA)/EE (Annovera, Mayne Pharma, Raleigh, NC, USA) ring. The details of dosing and administration, indications, advantages, disadvantages, and cost-effectiveness are presented. This literature review was conducted using PubMed and Google Scholar. The search terms included 'vaginal contraceptive ring', 'etonogestrel/ethinyl estradiol ring', and 'segesterone acetate/ethinyl estradiol ring'. The search was then sorted by year from 2000 until present, and the most recent articles were reviewed. The purpose of this article is to provide a comprehensive reference on the two vaginal contraceptive rings widely used in the United States for clinicians to guide management. Both vaginal contraceptive rings are combination of hormonal contraceptives that suppress ovulation and create physiologic conditions unfavorable for pregnancy. The ENG/EE ring is designed to be replaced monthly, while the SA/EE ring is a single device used over the course of 1 year. Common side effects of both devices include headaches, nausea, vomiting, and vaginitis. Serious adverse reactions can occur with the vaginal contraceptive rings including venous thromboembolism, psychiatric events, and hypersensitivity. Both devices are contraindicated in patients at high risk for arterial or venous thrombotic events, patients with a history of breast cancer or other estrogen/progesterone cancers, and patients with severe liver disease. Overall, the vaginal contraceptive ring is well tolerated and liked by patients. Patients should be well counseled on known severe adverse reactions. The vaginal contraceptive ring is more expensive than other forms of contraception and this should be an important point of discussion with patients.

Engineering a degradable polyurethane intravaginal ring for sustained delivery of dapivirine

We describe the engineering of a degradable intravaginal ring (IVR) for the delivery of the potent HIV-1 reverse transcriptase inhibitor dapivirine. The degradable polymer used in fabricating the device incorporated poly(caprolactone) ester blocks in a poly(tetramethylene ether) glycol ABA type polyurethane backbone. The polymer was designed to maintain its structure for 1 month during usage and then degrade in the environment post-disposal. In vitro release of dapivirine showed zero-order kinetics for up to 1 month and significant levels of drug release into engineered vaginal tissue. The mechanical properties of the degradable IVR were comparable to those of a widely used contraceptive intravaginal ring upon exposure to simulated vaginal conditions. Incubation under simulated vaginal conditions for a month caused minimal degradation with minimal effect on the mechanical properties of the ring and polymer. The cytotoxicity evaluation of the drug-loaded IVRs against Vk2/E6E7 human vaginal epithelial cells, Lactobacillus jensenii, and engineered vaginal tissue constructs showed the degradable polyurethane to be non-toxic. In vitro evaluation of inflammatory potential monitored through the levels of inflammatory cytokines IL-8, IL-1α, IL-6, IL-1β, and MIP-3α when engineered EpiVaginal™ tissue was incubated with the polyurethanes suggested that the degradable polyurethane was comparable to commercial medical grade polyurethane. These results are encouraging for further development of this degradable IVR for topical vaginal delivery of microbicides.

Inadvertent intravesicular placement of a vaginal contraceptive ring: a case report and review of literature

The NuvaRing® is a deformable, ring-shaped hormonal contraceptive device which is typically vaginally self-inserted by the patient. While there are several potential side effects of usage, essentially all of them result from hormone delivery. Complications from incorrect placement are rare. We present the case of a 31 year old female who presented to our emergency department after being unable to retrieve a NuvaRing® for its scheduled removal. CT scan showed a hypodense intravesicular NuvaRing® which the patient had inadvertently placed transurethrally 3 weeks prior. Cystoscopy was performed and retrieval using a 3-pronged grasper was eventually successful after several failed attempts with an alligator grasper. Our purpose in presenting this case is to introduce the reader to a rare complication of incorrect NuvaRing® placement, explain how this complication may occur as a result of NuvaRing® construction/functionality, describe how alternative cystoscopic instruments may aid in cystoscopic retrieval, and review the 3 other case reports of intravesicular NuvaRing® placement to discuss the utility of various imaging modalities when clinical suspicion of the complication is high.

Contraception for adolescents

A working knowledge of contraception will assist the pediatrician in both sexual health promotion as well as treatment of common adolescent gynecologic problems. Best practices in adolescent anticipatory guidance and screening include a sexual health history, screening for pregnancy and sexually transmitted infections, counseling, and if indicated, providing access to contraceptives. Pediatricians' long-term relationships with adolescents and families allow them to help promote healthy sexual decision-making, including abstinence and contraceptive use. Additionally, medical indications for contraception, such as acne, dysmenorrhea, and heavy menstrual bleeding, are frequently uncovered during adolescent visits. This technical report provides an evidence base for the accompanying policy statement and addresses key aspects of adolescent contraceptive use, including the following: (1) sexual history taking, confidentiality, and counseling; (2) adolescent data on the use and side effects of newer contraceptive methods; (3) new data on older contraceptive methods; and (4) evidence supporting the use of contraceptives in adolescent patients with complex medical conditions.

Vaginal health in contraceptive vaginal ring users - A review

BACKGROUND

To provide an overview of the available data from clinical studies of vaginal conditions in women who use a vaginal ring as a contraceptive.

METHODS

A systematic review of the literature.

RESULTS

Millions of women have already used the ethylene vinyl acetate vaginal ring that releases ethinylestradiol and etonogestrel for contraception. Because of its small size, more than four out of five women using the ring report that they do not feel it, even during sexual intercourse. No colposcopic or cytological changes have been observed in users, although approximately 10% have increased vaginal discharge. While in vitro studies have shown adhesion of Candida yeasts to the vaginal ring surface, clinical studies have not demonstrated a greater incidence of Candida infections compared to users of equivalent oral contraceptives. Some clinical studies suggest a lower incidence of bacterial vaginosis. No interaction exists between concomitant use of the vaginal ring and other drugs or products for vaginal use.

CONCLUSION

The use of a contraceptive vaginal ring does not alter the vaginal ecosystem and therefore does not substantially affect vaginal health.

A 90-day tenofovir reservoir intravaginal ring for mucosal HIV prophylaxis

A vaginal gel containing the antiretroviral tenofovir (TFV) recently demonstrated 39% protection against HIV infection in women. We designed and evaluated a novel reservoir TFV intravaginal ring (IVR) to potentially improve product effectiveness by providing a more controlled and sustained vaginal dose to maintain cervicovaginal concentrations. Polyurethane tubing of various hydrophilicities was filled with a high-density TFV/glycerol/water semisolid paste and then end-sealed to create IVRs. In vitro, TFV release increased with polyurethane hydrophilicity, with 35 weight percent water-swelling polyurethane IVRs achieving an approximately 10-mg/day release for 90 days with mechanical stiffness similar to that of the commercially available NuvaRing. This design was evaluated in two 90-day in vivo sheep studies for TFV pharmacokinetics and safety. Overall, TFV vaginal tissue, vaginal fluid, and plasma levels were relatively time independent over the 90-day duration at approximately 10(4) ng/g, 10(6) ng/g, and 10(1) ng/ml, respectively, near or exceeding the highest observed concentrations in a TFV 1% gel control group. TFV vaginal fluid concentrations were approximately 1,000-fold greater than levels shown to provide significant protection in women using the TFV 1% gel. There were no toxicological findings following placebo and TFV IVR treatment for 28 or 90 days, although slight to moderate increases in inflammatory infiltrates in the vaginal epithelia were observed in these animals compared to naïve animals. In summary, the controlled release of TFV from this reservoir IVR provided elevated sheep vaginal concentrations for 90 days to merit its further evaluation as an HIV prophylactic.

Quantitative evaluation of a hydrophilic matrix intravaginal ring for the sustained delivery of tenofovir

In vitro testing and quantitative analysis of a matrix, hydrophilic polyether urethane (HPEU) intravaginal ring (IVR) for sustained delivery of the anti-HIV agent tenofovir (TFV) are described. To aid in device design, we employed a pseudo-steady-state diffusion model to describe drug release, as well as an elastic mechanical model for ring compression to predict mechanical properties. TFV-HPEU IVRs of varying sizes and drug loadings were fabricated by hot-melt extrusion and injection molding. In vitro release rates of TFV were measured at 37 °C and pH 4.2 for 30 or 90 days, during which times IVR mechanical properties and swelling kinetics were monitored. Experimental data for drug release and mechanical properties were compared to model predictions. IVRs loaded with 21% TFV (w/w) released greater than 2mg TFV per day for 90 days. The diffusion model predicted 90 day release data by extrapolating forward from the first 7 days of data. Mechanical properties of IVRs were similar to NuvaRing, although the matrix elastic modulus decreased up to three-fold following hydration. This is the first vaginal dosage form to provide sustained delivery of milligram quantities of TFV for 90 days. Drug release and mechanical properties were approximated by analytical models, which may prove useful for the continuing development of IVRs for HIV prevention or other women's health indications.

Vaginal distribution and retention of a multiparticulate drug delivery system, assessed by gamma scintigraphy and magnetic resonance imaging

BACKGROUND

For any new vaginal dosage form, the distribution and retention in the vagina has to be assessed by in vivo evaluation. We evaluated the vaginal distribution and retention of starch-based pellets in sheep as live animal model by gamma scintigraphy (using Indium-111 DTPA as radiolabel) and in women via magnetic resonance imaging (MRI, using a gadolinium chelate as contrast agent). A conventional cream formulation was used as reference in both studies.

METHOD

Cream and pellets were administered to sheep (n=6) in a two period-two treatment study and to healthy female volunteers (n=6) via a randomized crossover trial. Pellets (filled into hard gelatin capsule) and cetomacrogol cream, both labeled with Indium-111 DTPA (for gamma scintigraphy) or with gadolinium chelate (for MRI) were evaluated for their intravaginal distribution and retention over a 24h period. Spreading in the vagina was assessed based on the part of the vagina covered with formulation (expressed in relation to the total vaginal length). Vaginal retention of the formulation was quantified based on the radioactivity remaining in the vaginal area (sheep study), or qualitatively evaluated (women study).

RESULTS

Both trials indicated a rapid distribution of the cream within the vagina as complete coverage of the vaginal mucosa was seen 1h after dose administration. Clearance of the cream was rapid: about 10% activity remained in the vaginal area of the sheep 12h post-administration, while after 8h only a thin layer of cream was detected on the vaginal mucosa of women. After disintegration of the hard gelatin capsule, the pellet formulation gradually distributed over the entire vaginal mucosa. Residence time of the pellets in the vagina was longer compared to the semi-solid formulation: after 24h 23 ± 7% radioactivity was detected in the vaginal area of the sheep, while in women the pellet formulation was still detected throughout the vagina.

CONCLUSION

A multi-particulate system containing starch-based pellets was identified as a promising novel vaginal drug delivery system, resulting in complete coverage of the vaginal mucosa and long retention time.

Examining the efficacy, safety, and patient acceptability of the combined contraceptive vaginal ring (NuvaRing)

The contraceptive vaginal ring is a novel contraceptive method that offers unique advantages. Intravaginal delivery of both estrogen and progesterone allows continuous release of medication, resulting in lower systemic levels. The use of long-term combined hormonal contraception enables improved cycle control compared with progesterone-only methods. The indications and usage of the NuvaRing^® are described along with the efficacy, tolerability, and safety. Overall, the contraceptive vaginal ring appears to be very effective, with a favorable side-effect profile, and is highly acceptable to most patients.

Compartmental transport model of microbicide delivery by an intravaginal ring

Topical antimicrobials, or microbicides, are being developed to prevent HIV transmission through local, mucosal delivery of antiviral compounds. While hydrogel vehicles deliver the majority of current microbicide products, intravaginal rings (IVRs) are an alternative microbicide modality in preclinical development. IVRs provide a long-term dosing alternative to hydrogel use, and might provide improved user adherence. IVR efficacy requires sustained delivery of antiviral compounds to the entire vaginal compartment. A two-dimensional, compartmental vaginal drug transport model was created to evaluate the delivery of drugs from an intravaginal ring. The model utilized MRI-derived ring geometry and location, experimentally defined ring fluxes and vaginal fluid velocities, and biophysically relevant transport theory. Model outputs indicated the presence of potentially inhibitory concentrations of antiviral compounds along the entire vaginal canal within 24 h following IVR insertion. Distributions of inhibitory concentrations of antiviral compounds were substantially influenced by vaginal fluid flow and production, while showing little change due to changes in diffusion coefficients or ring fluxes. Additionally, model results were predictive of in vivo concentrations obtained in clinical trials. Overall, this analysis initiates a mechanistic computational framework, heretofore missing, to understand and evaluate the potential of IVRs for effective delivery of antiviral compounds.

Segmented polyurethane intravaginal rings for the sustained combined delivery of antiretroviral agents dapivirine and tenofovir

Dual segment polyurethane intravaginal rings (IVRs) were fabricated to enable sustained release of antiretroviral agents dapivirine and tenofovir to prevent the male to female sexual transmission of the human immunodeficiency virus. Due to the contrasting hydrophilicity of the two drugs, dapivirine and tenofovir were separately formulated into polymers with matching hydrophilicity via solvent casting and hot melt extrusion. The resultant drug loaded rods were then joined together to form dual segment IVRs. Compression testing of the IVRs revealed that they are mechanically comparable to the widely accepted NuvaRing IVR. Physical characterization of the individual IVR segments using wide angle X-ray scattering and differential scanning calorimetry determined that dapivirine and tenofovir are amorphous and crystalline within their polymeric segments, respectively. In vitro release of tenofovir from the dual segment IVR was sustained over 30 days while dapivirine exhibited linear release over the time period. A 90 day accelerated stability study confirmed that dapivirine and tenofovir are stable in the IVR formulation. Altogether, these results suggest that multisegment polyurethane IVRs are an attractive formulation for the sustained vaginal delivery of drugs with contrasting hydrophilicity such as dapivirine and tenofovir.

Drug delivery for in vitro fertilization: rationale, current strategies and challenges

In vitro fertilization has experienced phenomenal progress in the last thirty years and awaits the additional refinement and enhancement of medication delivery systems. Opportunity exists for the novel delivery of gonadotropins, progesterone and other adjuvants. This review highlights the rationale for various medications, present delivery methods and introduces the status of novel ideas and possibilities.

Topical microbicides to prevent HIV: clinical drug development challenges

Microbicides, substances applied topically to prevent sexual HIV infection, are needed to empower receptive sexual partners with effective prevention methods. Several large microbicide trials, however, failed to demonstrate efficacy, thus motivating a reevaluation of the current microbicide development paradigm, which has been largely empirically based. Microbicide use occurs in a highly complex environment involving multi-level interactions, behavioral and biochemical, among host, virus, and drug, yet many details of these interactions remain unknown. Fundamental information regarding virus and drug distribution over time in sexually receptive body compartments that is necessary to design a microbicide able to outdistance and outlast the virus is largely absent. Recent efforts have been made to establish a simple conceptual framework for obtaining the knowledge that is likely to inform a more mechanistic, model-based development paradigm. These efforts have also advanced the development of numerous methodological approaches to obtain the knowledge needed to improve microbicide development.

Magnetic resonance imaging of SILCS diaphragm: anatomical considerations and corroboration with clinical fit

BACKGROUND

We performed a pilot study to evaluate in vivo the fit of the new SILCS diaphragm, a single-size cervical barrier, using magnetic resonance imaging (MRI) in a group of women varying in body mass and parity.

STUDY DESIGN

Two healthy premenopausal women were recruited for each of the following groups: body mass index (BMI)<25, BMI=25-30 and BMI>30. One woman in each group was nulliparous and one was multiparous. Subjects were instructed on the placement of the SILCS diaphragm. Each subject underwent three MRI scans: baseline, with the SILCS diaphragm in place and after placement of intravaginal contrast and simulated intercourse.

RESULTS

The SILCS diaphragm was easily identified on MRI. In all subjects, the diaphragm covered the cervix. The position of the diaphragm did not change after simulated intercourse. The appropriate position of the diaphragm, as assessed by the subjects and the practitioner, was corroborated by the MR images. The intravaginal contrast was not readily visible on the images, precluding assessment of the diaphragm's barrier properties.

CONCLUSION

MRI confirms the anatomic position of the SILCS diaphragm in vivo, among a sample of women varying in body mass and parity.

The combined etonogestrel/ethinyl estradiol contraceptive vaginal ring

Many factors influence the effectiveness of contraceptive methods. Oral contraceptives are the second most popular contraceptive method after female sterilization in the US. A total of 25% of women do not use their oral contraceptives correctly; 30% of women do not use them consistently. Several new contraceptive methods with alternate routes of delivery and less frequent dosing are available. The combined etonogestrel/ethinyl estradiol contraceptive vaginal ring is marketed under the name of NuvaRing. This is the only contraceptive ring approved by the FDA. The administration of steroids by the vaginal route may offer many advantages. Because of less frequent dosing, self-administration, and possibly, an improved side effect profile, the ring has the potential to increase successful use.

Factors affecting women's selection of a combined hormonal contraceptive method: the TEAM-06 Spanish cross-sectional study

BACKGROUND

Contraceptive efficacy and side effects are primary concerns of women when choosing a contraceptive method.

STUDY DESIGN

This cross-sectional multicenter study was designed to assess the reasons for selecting the contraceptive pill, the skin patch or the vaginal ring in 9700 women, aged 18-49 years, who consulted their doctors for starting or re-initiating combined hormonal contraception. A self-administered questionnaire regarding the reasons for the selection made and for the refusal of the remaining two methods was completed.

RESULTS

The vaginal ring showed the highest acceptance (46%) compared with the pill (39%) and the skin patch (15%), particularly in women aged 35-39 years. The ring and the skin patch were mainly preferred because of the lower probability of inadvertent omission (62% of cases), convenience, and monthly or weekly frequency of use. The pill was preferred because of its proven efficacy (60% of cases) and ease of use. The acceptance of the skin patch increased with age and the pill was mostly accepted only by women in the youngest age groups.

CONCLUSIONS

Convenience, frequency of use and lower probability of inadvertent omission were the primary determinants of contraceptive choice rather than the women's profile.