Comparison of spermicides on vulvar, vaginal, and cervical mucosa

Reversible female contraceptives: historical, current, and future perspectives†

Contraception is a practice with extensive and complicated social and scientific histories. From cycle tracking, to the very first prescription contraceptive pill, to now having over-the-counter contraceptives on demand, family planning is an aspect of healthcare that has undergone and will continue to undergo several transformations through time. This review provides a comprehensive overview of current reversible hormonal and non-hormonal birth control methods as well as their mechanism of action, safety, and effectiveness specifically for individuals who can become pregnant. Additionally, we discuss the latest Food and Drug Administration (FDA)-approved hormonal method containing estetrol and drospirenone that has not yet been used worldwide as well as the first FDA-approved hormonal over-the-counter progestin-only pills. We also review available data on novel hormonal delivery through microchip, microneedle, and the latest FDA-approved non-hormonal methods such as vaginal pH regulators. Finally, this review will assist in advancing female contraceptive method development by underlining constructive directions for future pursuits. Information was gathered from the NCBI and Google Scholars databases using English and included publications from 1900 to present. Search terms included contraceptive names as well as efficacy, safety, and mechanism of action. In summary, we suggest that investigators consider the side effects and acceptability together with the efficacy of contraceptive candidate towards their development.

Evaluating operational parameters of the careHPV, GeneXpert, AmpFire, and MA-6000 HPV systems for cervical precancer screening: Experience from Battor, Ghana

In response to calls by the World Health Organization for cervical precancer screening services in low-resource settings to lean toward HPV DNA testing, a number of testing platforms have been made available. This study aimed to evaluate the operational parameters of four HPV testing systems in previous (careHPV) and current (GeneXpert, AmpFire, and MA-6000) use in a secondary healthcare setting in terms of 'appropriateness', ease of use, throughput, and diagnostic yield. This descriptive retrospective cohort analysis included 6056 women who presented to our facility between June 2016 and March 2022 for cervical precancer screening via HPV testing. A large majority of this cohort underwent AmpFire testing (55.8%), followed by careHPV (23.3%), MA-6000 (14.7%), and GeneXpert (6.1%). MA-6000 showed the highest hr-HPV positivity rate of 26.4% (95% CI, 23.6-29.5), followed by AmpFire (17.2%; 95% CI, 15.9-17.5). GeneXpert and careHPV showed similar hr-HPV positivity rates of 14.8% (95% CI, 11.3-18.8) and 14.8% (95% CI, 13.0-16.8), respectively. For the AmpFire and MA-6000 platforms, which utilize similar detection and reporting formats, we found a significant excess detection rate of 9.2% (95% CI, 6.1-12.4; p-value <0.0001) for MA-6000 compared to AmpFire. At the genotype level, MA-6000 also detected significantly higher rates of HPV 16 and other hr-HPV types (both p-values <0.001) than AmpFire; there was no difference in detection for HPV 18. Based on our experiences and preliminary analysis, we believe that the choice of HPV testing platform cannot be accomplished with a one-size-fits-all approach. Factors worth considering are the financial implications of platform acquisition, costs to clients, and throughput when screening programs are not sufficiently large. We describe our successes and challenges with the different platforms which we believe will be helpful to centers in low-income countries as they transition into using HPV DNA testing for cervical precancer screening.

Serine protease inhibitor disrupts sperm motility leading to reduced fertility in female mice†

Inhibition of the sperm transport process in the female reproductive tract could lead to infertility. We previously showed that a pan-serine protease inhibitor, 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), blocked semen liquefaction in vivo and resulted in a drastic decrease in the number of sperm in the oviduct of female mice. In this study, we used a mouse model to test the efficacy of AEBSF as a reversible contraceptive, a sperm motility inhibitor, and a spermicide. Additionally, this study evaluated the toxicity of AEBSF on mouse vaginal tissues in vivo and human endocervical cells in vitro. We found that female mice treated with AEBSF had significantly less pups born per litter as well as fertilization rates in vivo compared to the vehicle control. We then showed that AEBSF reduced sperm motility and fertilization capability in vitro in a dose-dependent manner. Furthermore, AEBSF also exhibited spermicidal effects. Lastly, AEBSF treatment in female mice for 10 min or 3 consecutive days did not alter vaginal cell viability in vivo, similar to that of the vehicle and non-treated controls. However, AEBSF decreased cell viability of human ectocervical (ECT) cell line in vitro, suggesting that cells in the lower reproductive tract in mice and humans responded differently to AEBSF. In summary, our study showed that AEBSF can be used as a prototype compound for the further development of novel non-hormonal contraceptives for women by targeting sperm transport in the female reproductive tract.

Vaginal irritation models: the current status of available alternative and in vitro tests

Mucosal surfaces, such as the vaginal epithelium, are natural barriers to infection that are constantly exposed to bacteria and viruses, and are therefore potential sites of entry for numerous pathogens. The vaginal epithelium can be damaged mechanically, e.g. by the incorrect use of objects such as tampons, and by chemicals that are irritating or corrosive. Consequently, this can lead to an increase in susceptibility to further damage or infection. Pharmaceutical, cosmetic and personal care products that are specifically formulated for application onto human external mucosae can occasionally induce undesirable local or systemic side-effects. Therefore, the compatibility of applied materials with this mucosal surface represents a key issue to be addressed by manufacturers. The most frequently used method for assessing vaginal mucosal irritation is the in vivo rabbit vaginal irritation test. However, the current emphasis in the field of toxicology is to use alternative in vitro methods that reduce, refine, and replace the use of animals, and which model and predict human, not animal, responses. Such an approach is of particular interest to the personal care and cosmetic industries in their effort to comply with European legislative measures, such as the 7th Amendment to the EU Cosmetics Directive that does not permit the marketing of cosmetic products if they, or their ingredients, have been tested for irritation responses in animals. The focus of this review is to provide an overview of the alternative and in vitro tests that are currently available for vaginal mucosal irritation assessment, and which are already used, or may become useful, to establish the safety of newly-designed products for human use.

Cervicovaginal colposcopic lesions associated with 5 nonoxynol-9 vaginal spermicide formulations

OBJECTIVE

This study was undertaken to compare the colposcopic appearance of the cervicovaginal epithelium with spermicide use vs condom use in a low-risk population.

STUDY DESIGN

This was an ancillary study of a trial comparing the efficacy of 5 nonoxynol-9 spermicides. A cohort of women who used condoms without spermicide served as a control group. Colposcopic examinations were performed during product use to identify genital lesions.

RESULTS

One hundred fifty-one participants had 1 or more follow-up examinations. At baseline, study groups differed only by the prevalence of baseline lesions. New lesions were identified at 49% of follow-up visits. Controlling for the presence of a baseline lesion, compared with condom use none of the spermicides were associated with an increase in new lesions (overall odds ratio, 0.8; 95% CI, 0.4-1.6; P = .5); and lesions characterized by epithelial disruption were less frequent with spermicide use (overall odds ratio, 0.3; 95% CI, 0.1-0.6; P < .001).

CONCLUSION

In a low-risk population, women who used nonoxynol-9 spermicides were less likely to have lesions with epithelial disruption, and equally likely to have any new lesion compared with condom use.

Comparative safety evaluation of the candidate vaginal microbicide C31G

C31G is currently the focus of clinical trials designed to evaluate this agent as a microbicidal and spermicidal agent. In the following studies, the in vivo safety of C31G was assessed with a Swiss Webster mouse model of cervicovaginal toxicity and correlated with results from in vitro cytotoxicity experiments and published clinical observations. A single exposure of unformulated 1% C31G resulted in mild-to-moderate epithelial disruption and inflammation at 2 and 4 h postapplication. The columnar epithelium of the cervix was the primary site of damage, while no perturbation of the vaginal mucosa was observed. In contrast, application of unformulated 1.7% C31G resulted in greater levels of inflammation in the cervical epithelium at 2 h postapplication and severe epithelial disruption that persisted to 8 h postapplication. Application of a nonionic aqueous gel formulation containing 1% C31G resulted in no apparent cervicovaginal toxicity at any time point evaluated. However, formulation of 1.7% C31G did not substantially reduce the toxicity associated with unformulated C31G at that concentration. These observations correlate with findings gathered during a recent clinical trial, in which once-daily applications resulted in no adverse events in women receiving the formulation containing 1% C31G, compared to moderate-to-severe adverse events in 30% of women receiving the 1.7% C31G formulation. The Swiss Webster mouse model was able to effectively discriminate between concentrations and formulations of C31G that produced distinct clinical effects in human trials. The Swiss Webster animal model may be a highly valuable tool for preclinical evaluation of candidate vaginal microbicides.

Contraception by Ushercell™ (cellulose sulfate) in formulation: duration of effect and dose effectiveness

This study evaluated contraception by formulated Ushercell, a uniquely high-molecular-weight form of cellulose sulfate, in the rabbit. Variables included (1) dose effectiveness, (2) duration of effectiveness, and (3) formulation excipients. Vaginally applied carboxymethyl-cellulose-based Ushercell gel is contraceptive. A 6% gel is active for at least 18 h; partial activity is observed for at least 24 h. With an application-insemination interval of 0.5 h, Ushercell as low as 0.1% is contraceptive. Contraception is incomplete with 2% Ushercell and an application-insemination interval of 24 h. Ushercell formulations containing a relatively high concentration of Carbopol are ineffective contraceptives, whether the gel is applied before insemination or is premixed with spermatozoa before insemination. Contraceptive activity is restored in Ushercell formulations with lower Carbopol content. This study shows that formulated Ushercell is an effective, long-lasting contraceptive and, hence, is bioavailable when vaginally applied. Activity is dependent on the type and relative concentration of formulation excipients. These data support a projected successful outcome of further clinical trials.

Mouse model of cervicovaginal toxicity and inflammation for preclinical evaluation of topical vaginal microbicides

Clinical trials evaluating the efficacy of nonoxynol-9 (N-9) as a topical microbicide concluded that N-9 offers no in vivo protection against human immunodeficiency virus type 1 (HIV-1) infection, despite demonstrated in vitro inactivation of HIV-1 by N-9. These trials emphasize the need for better model systems to determine candidate microbicide effectiveness and safety in a preclinical setting. To that end, time-dependent in vitro cytotoxicity, as well as in vivo toxicity and inflammation, associated with N-9 exposure were characterized with the goal of validating a mouse model of microbicide toxicity. In vitro studies using submerged cell cultures indicated that human cervical epithelial cells were inherently more sensitive to N-9-mediated damage than human vaginal epithelial cells. These results correlated with in vivo findings obtained by using Swiss Webster mice in which intravaginal inoculation of 1% N-9 or Conceptrol gel (containing 4% N-9) resulted in selective and acute disruption of the cervical columnar epithelial cells 2 h postapplication accompanied by intense inflammatory infiltrates within the lamina propria. Although damage to the cervical epithelium was apparent out to 8 h postapplication, these tissues resembled control tissue by 24 h postapplication. In contrast, minimal damage and infiltration were associated with both short- and long-term exposure of the vaginal mucosa to either N-9 or Conceptrol. These analyses were extended to examine the relative toxicity of polyethylene hexamethylene biguanide (PEHMB), a polybiguanide compound under evaluation as a candidate topical microbicide. In similar studies, in vivo exposure to 1% PEHMB caused minimal damage and inflammation of the genital mucosa, a finding consistent with the demonstration that PEHMB was >350-fold less cytotoxic than N-9 in vitro. Collectively, these studies highlight the murine model of toxicity as a valuable tool for the preclinical assessment of toxicity and inflammation associated with exposure to candidate topical microbicides.

Interleukin (IL)-1, IL-6, and IL-8 predict mucosal toxicity of vaginal microbicidal contraceptives

Inflammation of the female reproductive tract increases susceptibility to HIV-1 and other viral infections and, thus, it becomes a serious liability for vaginal products. Excessive release of proinflammatory cytokines may alter the mucosal balance between tissue destruction and repair and be linked to enhanced penetration and replication of viral pathogens upon chemical insult. The present study evaluates four surface-active microbicide candidates, nonoxynol-9 (N-9), benzalkonium chloride (BZK), sodium dodecyl sulfate, and sodium monolaurate for their activity against human sperm and HIV, and their capacity to induce an inflammatory response on human vaginal epithelial cells and by the rabbit vaginal mucosa. Spermicidal and virucidal evaluations ranked N-9 as the most potent compound but were unable to predict the impact of the compounds on vaginal cell viability. Interleukin (IL)-1 release in vitro reflected their cytotoxicity profiles more accurately. Furthermore, IL-1 concentrations in vaginal washings correlated with cumulative mucosal irritation scores after single and multiple applications (P < 0.01), showing BZK as the most damaging agent for the vaginal mucosa. BZK induced rapid cell death, IL-1 release, and IL-6 secretion. The other compounds required either more prolonged or repeated contact with the vaginal epithelium to induce a significant inflammatory reaction. Increased IL-8 levels after multiple applications in vivo identified compounds with the highest cumulative mucosal toxicity (P < 0.01). In conclusion, IL-1, IL-6, and IL-8 in the vaginal secretions are sensitive indicators of compound-induced mucosal toxicity. The described evaluation system is a valuable tool in identifying novel vaginal contraceptive microbicides, selecting out candidates that may enhance, rather than decrease, HIV transmission.

The Evaluation of the Local Tolerance of Vaginal Formulations, With or Without Nonoxynol-9, Using the Slug Mucosal Irritation Test

BACKGROUND

Frequent use of some vaginal formulations can induce mucosal irritation. Therefore, it is important to evaluate their vaginal tolerance.

GOAL

The goal of this study was to optimize the mucosal irritation test using slugs for the evaluation of the local tolerance of vaginal gels and investigate the relevance of the test.

STUDY DESIGN

The irritation potential of the gels was assessed by the amount of mucus produced during a repeated 30-minute contact period. Membrane damage was estimated from the release of proteins and enzymes. After optimization of the procedure, the local tolerance of several vaginal gels was evaluated.

RESULTS

Hydroxyethyl cellulose gel induced no irritation, because the mucus production and the protein release were low and no enzyme release was detected. Replens and K-Y jelly resulted in an increased mucus production; however, no increased protein and no enzyme release were detected. The nonoxynol-9-containing gels Protectaid, Advantage S, and Conceptrol caused a higher mucus production and an increased protein release and/or enzyme release, indicating severe irritation.

CONCLUSION

The mucosal irritation test using slugs can be used for local tolerance testing of vaginal formulations.

Disruption of the upper female reproductive tract epithelium by nonoxynol-9

Spermicides containing nonoxynol-9 (N-9) may increase HIV transmission. In women, intravaginal N-9 is found in the uterus shortly after its insertion. Exposure of the female upper reproductive tract to N-9 may alter epithelial integrity, thereby increasing HIV transmission risk. Our goal was to characterize the histological effects of N-9 on uterine epithelium in an animal model. Female mice were exposed to intravaginal or intrauterine Advantage-S (N-9), Replens, K-Y(R) jelly or water. After various exposure times, mice were sacrificed and stained uterine tissue sections were analyzed by a pathologist blinded to treatment.Intravaginal and intrauterine N-9 administration resulted in disruption of uterine epithelium compared to Replens, K-Y jelly or water. N-9 caused rapid (within 10 min), focal, uterine epithelial sloughing and complete epithelial loss within 24 h. Epithelial regeneration began 48 h after exposure N-9 and was completely restored within 72 h; the new epithelial layer, however, was composed of cuboidal cells instead of normally present columnar cells. In addition, hemorrhage and necrosis were present are all time points examined. Our results demonstrate for the first time that N-9 has a deleterious effect on uterine epithelium. Although these results were observed in a mouse model, similar disruption of the upper reproductive tract epithelium in women by N-9 may facilitate HIV infection and serve as an unrecognized portal of human HIV transmission.

Dextrin sulfate as a vaginal microbicide: randomized, double-blind, placebo-controlled trial including healthy female volunteers and their male partners

This randomized, placebo-controlled trial assessed the safety and acceptability of vaginally administered 0.125% dextrin sulfate (DS) gel in sexually active women and their male partners. A single 2-mL dose of study gel was self-administered every night over two 14-day periods separated by a 7-day interval, during which menses was expected to occur. Up to two supplementary doses per 24 hours were provided for use before sexual intercourse. Semistructured interview, colposcopy, and laboratory safety studies were used to assess adverse events. Male partners who agreed to participate in a substudy were exposed to gel through sexual intercourse during the second 14-day exposure period. Seventy-three women (36 DS recipients and 37 placebo recipients) used at least one application of gel, of whom 66 (33 DS recipients and 33 placebo recipients) completed follow-up. Eleven women (5 DS recipients and 6 placebo recipients) reported intermenstrual bleeding during gel use, which in most cases was light and resolved within 24 hours. Ten male partners (4 with DS exposure and 6 with placebo exposure) were enrolled in the study and all completed follow-up. There was no evidence of systemic toxicity or genital epithelial disruption attributable to DS gel.

Safety of single daily use for one week of C31G HEC gel in women

Genital irritation and user acceptability was compared after seven nightly bedtime exposures to 1.2% C31G hydroxyethyl cellulose (HEC), 2% nonoxynol-9 (N-9) (Gynol II) or HEC vehicle alone. Sixty healthy women over 18 years old at low risk for sexually transmitted disease with normal menses were randomly assigned to one of three groups. Entrance and exit pelvic exams documented vaginal pH and Gram stain. Genital irritation was assessed by patient diaries, a telephone call 24 to 48 h after first use, colposcopy done the day after last product use, and an acceptability questionnaire at exit. Eighty percent of the women using C31G HEC experienced symptoms of vaginal burning or heat compared to 25% of the N-9 users and 5% of the vehicle users. Colposcopic findings were similar for the active treatments of C31G HEC and N-9: 50% vs. 60% developed new lesions, 25% vs. 20% had lesions that disrupted epithelial integrity, and 50% vs. 45% had minor lesions, respectively. Findings with the HEC vehicle were half as frequent. Twelve percent of women had epithelial disruption that was assessed by the colposcopist as applicator-related. Gram stains were half as likely to show bacterial vaginosis after N-9 use (6 --> 3) and one fourth as likely after vehicle or C31G HEC use (4 --> 1). When asked if they would use the product if it were an effective contraceptive, 55% of the vehicle users, 35% of the N-9 users, and 25% of the C31G HEC users agreed. Product acceptability of C31G HEC was limited by the sensation of heat or burning. The C31G HEC product had a similar safety profile to N-9 in this comparative trial.

Phase 1 trial of the topical microbicide BufferGel: safety results from four international sites

AIM

To evaluate the safety of BufferGel (ReProtect LLC, Baltimore, MD), a spermicidal microbicide that acidifies semen and maintains the protective acidity of the vagina, in a high-dose tolerance trial.

METHODS

HIV/STD negative, sexually abstinent, and sexually active women in India, Thailand, Malawi, and Zimbabwe were asked to insert one applicator ( approximately 5 ml) of BufferGel vaginally twice per day for 14 days. Sexually active women agreed to have sex (while using BufferGel and nonlubricated condoms) at least twice per week.

RESULTS

In total, 98 women (30 sexually abstinent and 68 sexually active) were enrolled. Overall compliance with product use was 93%. Epithelial abnormalities detected by pelvic examination or colposcopy were uncommon (8 cases in 271 examinations). Irritation was reported by approximately one quarter of the women (0.58 events per woman-week) but was generally mild and of short duration. The prevalence of bacterial vaginosis (BV) fell significantly, from 30% at enrollment to 6% at one week, and 7% at two weeks of BufferGel use. Thirty-two women acquired microscopically detectable yeast during BufferGel exposure, but only 3 developed symptomatic vaginitis.

CONCLUSION

BufferGel appears to be safe and well tolerated by the cervicovaginal epithelium. Its effect on BV and yeasts merits further study.

The use of colposcopy in assessing vaginal irritation in research

Since the early 1990s, colposcopy of the vagina and cervix has been used in the development of vaginal products in order to detect epithelial changes that may increase the likelihood of HIV or acquisition of other sexually transmitted diseases. As part of a continued effort to examine and define the role of colposcopy in a research setting, the Contraceptive Research and Development Program (CONRAD) and the International Working Group on Microbicides (IWGM), in association with the United Nations Program for AIDS (UNAIDS) sponsored a conference entitled, 'The Use of Colposcopy in Assessing Vaginal Irritation in Research', held in Washington, DC in January 1999. This is a report of that conference. The World Health Organization's colposcopy procedure and nomenclature, published in 1995, were reviewed and changes were recommended. The revised procedure involves colposcopic examination of the external genitalia, naked eye examination of the cervix, fornices, and vaginal walls, followed by lavage and colposcopic examination of those areas, and sampling as appropriate for microscopic examination. Revised nomenclature replaces the terms used for findings with descriptions of what is actually seen. Digital video imaging and testing for inflammatory markers may be adjuncts to colposcopy and should be further studied. Other areas requiring additional research include the natural history of colposcopic changes, factors other than product use that may affect colposcopic findings, the clinical significance of findings, and the procedure which best assesses these findings.

Evaluation of the antifertility effect of magainin-A in rabbits: in vitro and in vivo studies

OBJECTIVE

To evaluate the safety and contraceptive potential of magainin-A in rabbits.

DESIGN

Controlled laboratory study.

SETTING

Department of Immunology, Institute for Research in Reproduction, Mumbai, Parel, India.

ANIMAL(S)

Forty-eight female New Zealand white rabbits.

INTERVENTION(S)

The effect of magainin-A on sperm motility (in vitro and in vivo studies) and on vaginal epithelium (histologic study) was assessed along with serum and liver biochemical profiles.

MAIN OUTCOME MEASURE(S)

Suitability of magainin-A for contraceptive use.

RESULT(S)

Magainin-A arrested sperm motility, and 1 mg of magainin-A administered intravaginally blocked conception. No histopathologic abnormalities in the vaginal tissue or any changes in serum biochemical profiles were observed.

CONCLUSION(S)

Magainin-A may be used as an effective and safe intravaginal contraceptive compound that also has antibacterial properties.

Study of the vaginal tolerance to Acidform, an acid-buffering, bioadhesive gel

Vaginal tolerance tests were performed with a new potential microbicidal and spermicidal product, an acid-buffering vaginal gel (Acidform) without or with nonoxynol-9 (N-9). The potential advantages over other vaginal products include keeping a low pH, decrease of the irritating effect of N-9 on the cervix or vaginal mucosa associated with greater retention of the product after application, and decreasing "messiness" as compared to other vaginal products. Three groups of six women were admitted and randomly assigned to use Acidform with 0%, 2.5%, and 5% N-9. Colposcopic evaluation for vulvar, vaginal, and cervical signs of irritation was performed and photographs were taken, following a specific World Health Organization protocol, at time 0, and after 24 h and 6 days of application of the gel. No irritation or symptom was reported by users of Acidform without N-9. A generalized and intense erythema in cervix was observed in 10 of 12 Acidform/N-9 users and abrasion occurred in nine of them. Vulvar irritation was seen in seven of these 10 volunteers. N-9 concentration in the gel (2.5% or 5.0%) was not related to the findings. No ulcer, exulceration, or de-epithelialization was observed. Acidform without N-9 was well tolerated by volunteers, but it was unable to protect the cervix, vagina, and vulva from the N-9 effects.

Variations in vaginal epithelial surface appearance determined by colposcopic inspection in healthy, sexually active women

A total of 107 sexually active women, aged 18-35 years, was recruited through family planning clinics in four centres in different countries. Each woman underwent two or three gentle but thorough and systematic vaginal inspections using a consistent technique with colposcopic magnification over a 4-6 month period to look for changes in vaginal and cervical appearance which might be related to sexual intercourse, tampon use, contraceptive method used, cigarette smoking or other environmental factors. Obvious changes in appearance were photographed at x10 magnification. These 'appearances' or 'conditions' were classified according to a modification of the recommendations of a workshop sponsored by the World Health Organization, the Population Council and the Conrad Program. Most of these alterations in the appearance of the vaginal epithelium were judged to be of such minor clinical importance that they have been termed 'conditions' or 'changes in appearance' rather than 'lesions'. In all, 56 'conditions' or 'appearances' were noted in 314 inspections, the commonest being petechiae (53.6%). Potentially significant conditions justifying the term 'lesions' (three microulcerations, two ecchymoses, five abrasions and one mucosal tear; 3.5% of inspections) usually healed spontaneously and disappeared rapidly. The incidence of these conditions was highest when the inspections followed intercourse in the previous 24 h (25.2 versus 14.2%; P < 0.0008), or tampon use (32.4 versus 15.9%; P < 0. 0001). These processes may be regarded as a reflection of regular minor trauma to the vaginal epithelium.

Safety of a nonoxynol-9 vaginal gel in Kenyan prostitutes. A randomized clinical trial

OBJECTIVE

To evaluate the safety and toxicity of once-daily administration of Advantage-24 (Columbia Research Laboratories, Inc., Rockville Centre, NY), a vaginal gel containing 52.5 mg of nonoxynol-9 (N-9), including the effects of this gel on the vaginal and cervical epithelium.

STUDY DESIGN

Randomized, placebo-controlled, double-blind crossover trial, with a 2-week product application period and a 2-week washout period.

METHODS

Female sex workers in Mombasa, Kenya were randomized to one of two sequences, N-9 followed by placebo, or vice versa. Women were instructed to apply one applicator of N-9 or placebo gel vaginally once each day. During each of the two product periods, subjects were evaluated by questionnaire and physical examination, including colposcopy, after 7 and 14 days of product use. The primary outcome was genital epithelial disruption.

RESULTS

Sixty subjects were randomized, of whom 52 (87%) had complete follow-up. There were four episodes of epithelial disruption, three of which occurred during the placebo period and one during the N-9 period. The estimated risk of epithelial disruption associated with N-9 use was 0.33 (95% confidence interval, 0.03-3.26). There was no increased frequency of other, nondisruptive epithelial lesions during N-9 use.

CONCLUSIONS

No genital epithelial toxicity of N-9 vaginal gel was observed. This safety profile suggests that this N-9 product is appropriate for evaluation for human immunodeficiency virus type 1 prevention in a phase III efficacy trial.