Spermicidal and antifertility effects of an imbibing and soluble nonoxynol-9 diaphragm (ISND) in rabbits.

OBJECTIVE: To determine the minimum effective concentration (MEC) of an imbibing and soluble nonoxynol-9 (N-9) diaphragm (ISND) required for immobilisation of all spermatozoa in vitro and in vivo. The speed of semen absorbance, time of ISND to dissolution, and the antifertility effects were also investigated in rabbits. METHODS: In vitro spermicidal tests with ISND were conducted using fresh semen from humans and rabbits. Spermicidal and antifertility effects were observed in vivo after the ISND was placed directly into the vagina of rabbits. RESULTS: The MEC of N-9 required in the ISND to totally immobilise sperm within 20 seconds was 0.15 mg/ml for human sperm, and 0.5 mg/ml for rabbit sperm. The human semen was absorbed into the ISND in 45 minutes; the diaphragm dissolved in the vagina 3.5 hours later. In vivo, in rabbits, the MEC of N-9 required to immobilise sperm within five minutes of mating was 1 mg/kg in the ISND, and 10 mg/kg for the nonoxynol-9 film. The median effective dose of N-9 in the ISND was 1.07 mg/kg, whereas for the film it was 3.30 mg/kg. CONCLUSION: The spermicidal and antifertility activities of a low dose N-9 in the ISND were high, with properties of imbibition and solubility confirmed.

Monitoring vaginal epithelial thickness changes noninvasively in sheep using optical coherence tomography.

OBJECTIVE: High-resolution optical coherence tomography can be used noninvasively to evaluate vaginal morphologic features, including epithelial thickness, to assess this protective barrier in transmission of sexually transmitted infections and to monitor tissue response to topical medications and hormonal fluctuations. We examined the use of optical coherence tomography to measure epithelial thickness noninvasively before and after topical treatment with a drug that causes epithelial thinning. STUDY DESIGN: Twelve female sheep were treated with intravaginal placebo (n = 4) or nonoxynol-9 (n = 8). Vaginal optical coherence tomography images were obtained before and 24 hours after treatment. Four sheep in the nonoxynol-9 group were also examined on days 3 and 7. Vaginal biopsies were obtained on the last examination day. Epithelial thickness was measured in optical coherence tomography images and in hematoxylin and eosin-stained histologic sections from biopsies. Statistical analysis was performed using analyses of variance (significance P < .05). RESULTS: Baseline optical coherence tomography epithelial thickness measurements were similar (85 ± 19 µm placebo, 78 ± 20 µm nonoxynol-9; P = .52). Epithelial thinning was significant after nonoxynol-9 (32 ± 22 µm) compared with placebo (80 ± 15 µm) 24 hours after treatment (P < .0001). In the 4 nonoxynol-9-treated sheep followed for 7 days, epithelial thickness returned to baseline by day 3, and increased significantly on day 7. Epithelial thickness measurements from histology were not significantly different than optical coherence tomography (P = .98 nonoxynol-9, P = .93 hydroxyethyl cellulose). CONCLUSION: Drug-induced changes in the epithelium were clearly detectable using optical coherence tomography imaging. Optical coherence tomography and histology epithelial thickness measurements were similar, validating optical coherence tomography as a noninvasive method for epithelial thickness measurement, providing an important tool for quantitative and longitudinal monitoring of vaginal epithelial changes.

Spermicide used alone for contraception.

BACKGROUND: Spermicides have been used as contraceptives for thousands of years. Despite this long use, only recently have studies examined the comparative efficacy and acceptability of these vaginal medications. Spermicides contain an active ingredient (most commonly nonoxynol-9) and a formulation used to disperse the product, such as foam or vaginal suppository. OBJECTIVES: This review examined all known randomized controlled trials of a spermicide used alone for contraception. SEARCH METHODS: In August 2013, we searched the following computerized databases for randomized controlled trials of spermicides for contraception: CENTRAL, MEDLINE, POPLINE, LILACS, EMBASE, ClinicalTrials.gov, and ICTRP. For the initial review, we examined the reference lists of trials found as well as those of review articles and textbook chapters. SELECTION CRITERIA: We included any trial of a commercial product used alone for contraception. Each included trial must have provided sufficient information to determine pregnancy rates. DATA COLLECTION AND ANALYSIS: Two authors independently extracted information from the trials identified. We did not conduct a meta-analysis, since most trials had large losses to follow up. We entered the data into tables and presented the results descriptively. MAIN RESULTS: We located reports from 14 trials for the initial review, but have not identified any new trials since then. In the largest trial to date, the gel (Advantage S) containing the lowest dose of nonoxynol-9 (52.5 mg) was significantly less effective in preventing pregnancy than were gels with higher doses of the same agent (100 mg and 150 mg). Probabilities of pregnancy by six months were 22% for the 52.5 mg gel, 16% for the 100 mg dose, and 14% for the 150 mg dose. In the same trial, the three different vehicles with 100 mg of nonoxynol-9 had similar efficacy. Interpretation of these figures is limited, since 39% of participants discontinued the method or were lost from the trial. Few important differences in efficacy emerged in other trials. AUTHORS' CONCLUSIONS: The probability of pregnancy varied widely in reported trials. A gel containing nonoxynol-9 52.5 mg was inferior to two other products tested in the largest trial. Aside from this finding, personal characteristics and behavior of users may be more important than characteristics of the spermicide products in determining the probability of pregnancy. Gel was liked more than the film or vaginal suppository in the largest trial. Spermicide trials have the dual challenges of difficult recruitment and high discontinuation rates; the latter threatens trial validity.

Functional attenuation of human sperm by novel, non-surfactant spermicides: precise targeting of membrane physiology without affecting structure.

BACKGROUND: We have attempted to identify structural, physiological and other targets on human sperm vulnerable to the spermicidal action of two novel series of non-detergent molecules, reported to irreversibly immobilize human sperm in <30 s, apparently without disrupting plasma membrane. METHODS: Three sperm samples were studied. Scanning and transmission electron microscopy were used to assess structural aberrations of sperm membrane; plasma membrane potential and intracellular pH measurements (fluorometric) were used to detect changes in sperm physiology; reactive oxygen species (ROS, fluorometric) and superoxide dismutase activity (colorimetric) were indicators of oxidative stress; and sperm dynein ATPase activity demonstrated alterations in motor energy potential, in response to spermicide treatment. Post-ejaculation tyrosine phosphorylation of human sperm proteins (immunoblotting) was a marker for functional integrity. RESULTS: Disulfide esters of carbothioic acid (DSE compounds) caused complete sperm attenuation at > or =0.002% concentration with hyper-polarization of sperm membrane potential (P < 0.001), intracellular alkalinization (P < 0.01), ROS generation (P < 0.05) and no apparent effect on sperm (n = 150) membrane structure. Isoxazolecarbaldehyde compounds required > or =0.03% for spermicidal action and caused disrupted outer acrosomal membrane structure, depolarization of membrane potential (P < 0.001), intracellular acidification (P < 0.01) and ROS generation (P < 0.01). Detergent [nonoxynol-9 (N-9)] action was sustainable at > or =0.05% and involved complete breakdown of structural and physiological membrane integrity with ROS generation (P < 0.001). All spermicides caused functional attenuation of sperm without inhibiting motor energetics. Unlike N-9, DSE-37 (vaginal dose, 200 microg) completely inhibited pregnancy in rats and vaginal epithelium was unchanged (24 h,10 mg). CONCLUSIONS: The study reveals a unique mechanism of action for DSE spermicides. DSE-37 holds promise as a safe vaginal contraceptive. CDRI Communication No. 7545.

Biocompatible polyvinyl alcohol and RISUG® blend polymeric films with spermicidal potential.

Majority of the commercially available vaginal contraceptives encompasses cervicovaginal membrane disrupting detergent molecules as pharmacologically active ingredients. Development of a tissue-compatible vaginal contraceptive agent is necessary to circumvent the existing demand for female contraception in the reproductive healthcare sector. With this objective, the present study delineates the use of RISUG® based non-hormonal female contraceptive films. RISUG® was blended with polyvinyl alcohol (PVOH) to formulate biodegradable intra-vaginal contraceptive films. The formulated films were characterized for their thermal, physiochemical and biological features. The results showed that both RISUG® and PVOH were miscible and interacted at the intermolecular level. Variations in the concentration of RISUG® resulted in the changes in physicochemical, thermal and rheological characteristics of the formulated blends. In vitro toxicological assay of the polymeric formulations did not show any significant toxicity. However, the blend films retained spermicidal potential of RISUG®. Furthermore, in vivo toxicological evaluation of the polymeric blend in the rat model revealed about their biocompatibility with no significant organ toxicity, hematological and biochemical alterations. These results together confirm the potential applicability of the PVOH:RISUG® blend films as a vaginal contraceptive.

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.

A Phase I study of the functional performance, safety and acceptability of the BufferGel Duet.

BACKGROUND: The purpose of this study was to assess the functional performance of the BufferGel Duet, a buffering microbicide and spermicide gel applied to the cervix and vagina by a novel applicator that also serves as a mechanical barrier. STUDY DESIGN: This was a noncomparative Phase I safety trial in 30 healthy couples, aged 20-50 years, at low risk for sexually transmitted infections, who agreed to use the gel-device combination twice in 1 week and respond to detailed questionnaires about their experience. The female participants were examined with colposcopy before and 6-18 h after using the second device. RESULTS: Based on written instructions alone, 25 women successfully placed and 28 women successfully removed the device. Three women reported feeling the device dislodge around the time of intercourse. The product was equally acceptable to both men and women. Most users concluded that intercourse was the same or better with the device than with no product. About 73% would choose Duet over male condoms, and no one preferred the standard diaphragm. Colposcopic findings were noted in 79% of women with external genital findings (9) or cervicovaginal peeling (18) predominating. Only one finding breached the epithelium. Most product-related adverse events were mild (10/11) and confined to the genitourinary tract. CONCLUSIONS: The successful placements and acceptability suggest that further product development is warranted and could target over-the-counter use. During increased duration of use or more frequent dosing, cervicovaginal monitoring is advised based on the extent of peeling and external colposcopic findings in this short-term study.

Contraceptive efficacy of a novel spermicidal microbicide used with a diaphragm: a randomized controlled trial.

OBJECTIVE: Women need products that protect against both pregnancy and sexually transmitted infections, including human immunodeficiency virus (HIV). The acid buffering gel is a nondetergent spermicide that may provide this dual protection by reinforcing normal vaginal acidity to inactivate both sperm and acid-sensitive sexually transmitted pathogens. The objective of this study was to assess the gel's contraceptive effects, safety, and acceptability. METHODS: We conducted a multicenter, randomized, double-masked, noninferiority study at 11 centers, comparing 621 women who used an acid buffering gel plus diaphragm with 300 women who used a nonoxynol-9 spermicide plus diaphragm for 6 months. A double-masked study extension followed 234 women for an additional 6 months of use. RESULTS: The 6-month pregnancy rate per hundred women was 10.1% (95% confidence interval [CI] 7.1-13.1%) for acid buffering gel and 12.3 (95% CI 7.7-16.9) for nonoxynol-9 spermicide users. The difference in rates was -2.2% with a 95% CI -7.7 to 3.3%. Consistent and correct use 6-month pregnancy rates were 4.7% for acid buffering gel and 6.1% for nonoxynol-9 spermicide users, calculated from those cycles where diary entries indicated such use. Adverse events and acceptability were similar between the two groups. Pregnancy probabilities were similar between groups participating in the 12-month study extension. CONCLUSION: An acid buffering gel used with a diaphragm is a safe, acceptable contraceptive with efficacy comparable to that of a common commercial spermicide with diaphragm. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.ClinicalTrials.gov, NCT00065858 LEVEL OF EVIDENCE: I.

Over-the-counter vaginal contraceptive and spermicide drug products containing nonoxynol 9; required labeling. Final rule.

The Food and Drug Administration (FDA) is issuing a final rule establishing new warning statements and other labeling information for all over-the-counter (OTC) vaginal contraceptive drug products (also known as spermicides, hereinafter referred to as vaginal contraceptives or vaginal contraceptives/spermicides) containing nonoxynol 9 (N9). These warning statements will advise consumers that vaginal contraceptives/spermicides containing N9 do not protect against infection from the human immunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS), or against getting other sexually transmitted diseases (STDs). The warnings and labeling information will also advise consumers that use of vaginal contraceptives and spermicides containing N9 can irritate the vagina and rectum and may increase the risk of getting the AIDS virus (HIV) from an infected partner. This final rule is part of FDA's ongoing review of OTC drug products. FDA is issuing this final rule after considering public comments on its proposed regulation, and all relevant data and information on N9 that have come to our attention.

The impact of the use of COL-1492, a nonoxynol-9 vaginal gel, on the presence of cervical human papillomavirus in female sex workers.

This study investigated the effectiveness of a nonoxynol-9 (52.5mg, 3.5%), vaginal gel (Advantage S), in the prevention of human papillomavirus (HPV) infection in female sex workers. We showed by HPV DNA determination in cervico-vaginal rinses a significant increase in multiple (>1) HPV infection in HIV-1 seropositive women compared with HIV-1 seronegative women (OR 4.0, 95% CI 1.3-11.9). We also demonstrated a significant increase in multiple HPV infections in HIV-1 seronegative women using nonoxynol-9 compared with HIV-1 seronegative women using placebo (OR 3.5 95% CI 1.0-11.8). We conclude that the use of nonoxynol-9 did not prevent genital HPV infection and could increase the virus' ability to infect or persist.

Acceptability of five nonoxynol-9 spermicides.

OBJECTIVE: To examine the acceptability of five nonoxynol-9 (N-9) spermicides. METHODS: We analyzed data from a randomized trial of five products, including three gels containing different amounts of N-9 per dose, a film and a suppository. In the trial, 1536 participants were asked to use the assigned spermicide for 7 months and to complete questionnaires 4 weeks after admission and at discontinuation. RESULTS: Overall, 43% of participants liked their spermicide "very much." This proportion was higher in the three gel groups than in the suppository and film groups. Difficulty with insertion, messiness and discontent with timing of insertion were common complaints in all groups. After adjustment for selected baseline factors, acceptability on the first questionnaire was not related to duration or consistency of subsequent spermicide use or to subsequent time to pregnancy. CONCLUSIONS: In this study, all five spermicides were considered acceptable by most users. Acceptability did not appear to influence spermicide use or pregnancy risk.

Lea's Shield: colposcopic and microbiological testing during 8 weeks of use.

OBJECTIVES: The aims of this study were to assess the effects of Lea's Shield(R) plus nonoxynol-9 spermicide on signs and symptoms of female genital irritation and cervical and vaginal microflora during 8 weeks of use with intercourse and to analyze problems associated with the use of the device. METHODS: In this open-label, single-arm study, participants were evaluated by pelvic examination, colposcopy and vaginal and cervical cultures. RESULTS: About 13% of women (4/30) reported symptoms of irritation, and minor product-related colposcopic findings were seen in about one third (11/30). Although average colony counts for enterococcus, Escherichia coli and anaerobic gram-negative rods increased during product use, no clinical diagnoses of infection were made. Most users reported at least one problem using Lea's Shield. CONCLUSION: Lea's Shield, when used for 8 weeks during intercourse, is associated with evidence of genital irritation in a minority of users and with changes in vaginal microflora that do not appear to correlate with clinical infections.

Rectal use of nonoxynol-9 among men who have sex with men.

OBJECTIVES: To assess recent rectal use of nonoxynol-9 (N-9), intent to use the product, and factors associated with N-9 use among men who have sex with men (MSM). DESIGN: Cross-sectional survey of a diverse sample of MSM in the San Francisco Bay Area. METHODS: Recruitment conducted at multiple street locations on various days/times or through referral during the Fall of 2001. RESULTS: Sixty-one percent (349/573) had heard of N-9, of which 55% (192/349) reported hearing in the prior year that N-9 may not be protective against HIV. Of men aware of N-9, 83% (289/349) knowingly used it in their lifetime, of which 67% (193/289) used it during anal intercourse in the previous year. Forty-one percent (79/193) of those who used N-9 during anal intercourse in the past year did so without a condom because they thought it may protect against HIV. Older men were more likely than younger men to have used N-9 for protection. Men who heard that N-9 may not protect were less likely, and African-Americans (versus Caucasians) were more likely, to say they would definitely use N-9 during anal intercourse in the future. Latinos (versus Caucasians), those with unknown HIV serostatus (versus HIV-negative), and those with lower education were less likely to know about N-9 at all, and thus were at risk for unknowingly using N-9. CONCLUSIONS: Many MSM used N-9 during or following public health warnings about the product. Actions (e.g., information campaigns, warning labels specific to rectal use) should be considered by communities to reduce rectal use of N-9.

Toxic-shock syndrome and the vaginal contraceptive sponge.

PIP: 4 reported cases of toxic shock syndrome (TSS) occurred in late 1983 among users of the vaginal contraceptive sponge (VCS). All patients manifested fever, hypotension, diffuse rash, desquamation, nausea, vomiting, myalgias, mucous membrane hyperemia, and vaginal discharge. All were hospitalized, treated with intravenous fluids and antimicrobial agents, and recovered. Vaginal cultures in each case were positive for Staphylococcus aureus. The VCS is made of polyurethane impregnated with the spermicide nonoxynol-9 and is intended to provide 24 hours of contraception. During clinical trials the average woman using only this method of contraception used 10 sponges/month. Package labels state that if symptoms compatible with TSS develop users should seek medical care. Women who use the VCS should read the package insert carefully and follow the manufacturer's directions. Women who have had TSS should consult a physician before using a VCS and so should postpartum women. If it is assumed that the 4 cases reported were attributable to a VCS, a minimum estimate of the incidence of nonmenstrual TSS associated with VCS use would be 10/year/100,000 women who use only VCS compared to 5-10/year/100,000 who use tampons. The use of contraceptive methods other than the VCS may also affect the risk of developing TSS; cases of nonemnstrual TSS among diaphragm users have been reported. Conversely the use of oral contraceptives may reduce the risk of developing menstrual TSS.^ieng

Contraceptive effectiveness of two spermicides: a randomized trial.

OBJECTIVE: We conducted a multinational randomized trial to determine whether a spermicidal film containing 72 mg of nonoxynol-9 per film was at least as effective in preventing pregnancy as a foaming tablet containing 100 mg of nonoxynol-9 per tablet. METHODS: Between September 1995 and July 1997, 765 women aged 18-35 years who had no evidence of subfecundity were randomly assigned to use one of the two spermicides as their only contraceptive method at every coital act for 28 weeks. Participants were asked to keep coital diaries throughout the study period. Pregnancy tests were performed on a scheduled basis. Each participant was followed for 28 weeks or until she stopped considering the spermicide as her primary method of contraception. RESULTS: The Kaplan-Meier estimate of the 6-month probability of pregnancy during typical use of the spermicide was 28.0% in the tablet group and 24.9% in the film group (P = .78, one-tailed test). The study had nearly 75% power to have detected a difference of seven percentage points between groups. Results were almost identical when the analysis included only months when the participants reported use of the spermicide during every coital act. Reported levels of sexual activity and compliance with use of the spermicide were high in both groups. CONCLUSION: The contraceptive effectiveness of these two spermicidal products appeared similar. Both products were associated with a fairly high risk of pregnancy in this young, highly sexually active population.

Contraceptive effectiveness and safety of five nonoxynol-9 spermicides: a randomized trial.

OBJECTIVES: To estimate and compare the effectiveness and safety of 5 spermicides over 6 and 7 months of use, respectively. The spermicides included 3 gels containing 52.5 mg, 100 mg, and 150 mg of nonoxynol-9 per dose and a film and a suppository, each containing 100 mg of nonoxynol-9 per dose. METHODS: Women wishing to use only spermicide for contraception for 7 months were randomly assigned to use 1 of the 5 spermicides with emergency contraception backup. Participants were followed up for up to 30 weeks after admission. RESULTS: Of 1,536 women enrolled, 868 (57%) either relied on the spermicide for 6 months or became pregnant. The probability of pregnancy during 6 months of typical use of the spermicide was 22% (95% confidence limits 16%, 28%) in the 52.5-mg gel group, 16% (10%, 21%) in the 100-mg gel group, 14% (9%, 19%) in the 150-mg gel group, 12% (7%, 17%) in the film group, and 10% (6%, 15%) in the suppository group. The pregnancy risk in the 52.5-mg gel group was significantly different (P <.05) from that in either of the other gel groups. The pregnancy risks in the three 100-mg product groups were not significantly different (P =.35). No significant differences among groups were found in the 7-month probability of specified urogenital conditions. CONCLUSION: The gel with the lowest amount of nonoxynol-9 was less effective than the 2 higher-dose gels. Among 3 products containing 100 mg of nonoxynol-9, formulation did not significantly affect pregnancy risk. All products were safe. LEVEL OF EVIDENCE: I

Contraceptive activity of a spermicidal aryl phosphate derivative of bromo-methoxy-zidovudine (compound WHI-07) in rabbits.

OBJECTIVE: To determine the vaginal contraceptive activity of WHI-07 in the rabbit model. DESIGN: Prospective, controlled study. SETTING: Center for advanced preclinical sciences. ANIMAL(S): Subgroups of 15, 16, or 24 New Zealand White does and 24 bucks per experiment. INTERVENTION(S): Ex vivo (Experiment 1) and in vivo (Experiments 2 and 3) treatment of semen with WHI-07 or Nonoxynol-9 (N-9). In Experiment I, ovulated does in subgroups of 15 were artificially inseminated with semen mixed with WHI-07 or vehicle. In Experiment 2, ovulated does in subgroups of 24 were artificially inseminated within 2 min after intravaginal administration of 2% WHI-07 gel-microemulsion or 2% N-9 gel and allowed to complete term pregnancy. In Experiment 3, ovulated does in subgroups of 16 were artificially inseminated at 15, 30, or 60 minutes. MAIN OUTCOME MEASURE(S): The numbers of implanted embryos on postinsemination day 8 or the proportion of does that became pregnant and delivered newborn rabbits; the litter size, weight, growth, and viability of pups until lactation day 5. RESULT(S): Exposure of semen to WHI-07 at the time of artificial insemination completely inhibited pregnancy rates (WHI-07-pretreated, 0%, vs. control, 60%) and embryo implantation (WHI-07-pretreated, 0/175 vs. control, 68/170). Intravaginal administration of a 2% WHI-07 gel-microemulsion or 2% N-9 gel before artificial insemination significantly inhibited pregnancy rates (81% and 85% inhibition, respectively) when compared with control. Furthermore, the 2% WHI-07 gel-microemulsion provided >90% inhibition of fertility even when insemination was delayed until 60 minutes after intravaginal application. Rabbits that delivered litters despite intravaginal application of 2% WHI-07 gel-microemulsion had healthy offsprings with no perinatal or postnatal repercussions. CONCLUSION(S): WHI-07 is a potent contraceptive agent in vivo. Intravaginal use of WHI-07 gel-microemulsion has clinical potential as a safe prophylactic contraceptive, in addition to its microbicide activity to curb the sexual transmission of HIV.

Assessment of a tablet drug delivery system incorporating nonoxynol-9 coprecipitated with polyvinylpyrrolidone in preventing the onset of pregnancy in rabbits.

OBJECTIVE: To assess the in vivo efficacy of the tablet drug delivery system containing nonoxynol-9 coprecipitated with polyvinylpyrrolidone by delivering the spermicidal agents vaginally and evaluating their ability to prevent the onset of pregnancy in rabbits. DESIGN: Controlled clinical study. SETTING: Division of Laboratory and Animal Resources, College of Pharmacy, University of Kentucky. ANIMAL(S): Forty-two New Zealand White female rabbits. INTERVENTION(S): The rabbits were artificially inseminated at various intervals after vaginal insertion of the tablet drug delivery system containing either polyvinylpyrrolidone only (0 minutes) or nonoxynol-9 coprecipitated with polyvinylpyrrolidone (polyvinylpyrrolidone/nonoxynol-9; 0, 3, 30, 180, and 360 minutes). The rabbits were induced to ovulate 6 hours before insemination by i.m. injection of hCG (200 IU). MAIN OUTCOME MEASURE(S): The onset of pregnancy in the rabbits was evaluated after insertion of the tablet drug delivery system containing polyvinylpyrrolidone only or polyvinylpyrrolidone/nonoxynol-9 at various intervals, followed by artificial insemination. RESULT(S): The onset of pregnancy was not reduced significantly when the tablet drug delivery system containing polyvinylpyrrolidone or polyvinylpyrrolidone/nonoxynol-9 was used and insemination was performed immediately after tablet insertion (time 0). However, pregnancy rates (PRs) were reduced significantly in the rabbits that received the tablet drug delivery system containing polyvinylpyrrolidone/nonoxynol-9 and were inseminated at 3, 30, 180, and 360 minutes after tablet insertion. The highest PR reduction occurred between 30 and 180 minutes after insertion of the tablet drug delivery system containing polyvinylpyrrolidone/nonoxynol-9. CONCLUSION(S): The tablet drug delivery system is an efficient method of delivering the tested spermicidal agents vaginally. The design and dosage used in preparing the tablet drug delivery system provide short- and long-term release of the spermicidal agents, which results in almost immediate and extended enhancement of their contraceptive properties.

Properties of a new, long-lasting vaginal delivery system (LASRS) for contraceptive and antimicrobial agents.

In view of the need for improved vaginal formulations that are contraceptive, that may prevent transmission of sexually transmitted infections, or both, a new delivery system (base formulation; called Long Acting, Sustained Release of Spermicide, or LASRS) was developed that contains bioadhesive and other ingredients with a long history of safety, and was designed to provide long-lasting vaginal retention of the formulation and to minimize possible vaginal irritation caused by incorporated active ingredients. Nonoxynol-9 (N-9) was added as an active ingredient to study the vaginal irritating properties of the formulation and to assess its long-term effectiveness by postcoital spermicidal tests. In the first series of experiments, in vitro studies showed that the formulation spreads rapidly over a cellulose membrane, forming a bioadhesive layer that remained for at least 12 hours. The second series of experiments addressed the safety of the LASRS suppository in rabbits and primates. Even with a very high concentration of N-9 (20.5%), LASRS caused only mild/moderate but acceptable irritation in the rabbit. No vaginal irritation occurred in the primate at an even higher concentration (22.5%). During the third series of experiments, the long-lasting vaginal retention properties were evaluated by postcoital spermicidal tests in the primate. LASRS with N-9 was highly spermicidal even when mating was delayed for 12 hours after placement of the formulation. Spermicidal activity was also observed when 1) mating was delayed for 24 hours after insertion of the formulation, and 2) if the females were mated 2 or even 3 times without reinsertion of the suppository before collection of the vaginal contents. In the final series of tests, the postcoital spermicidal properties of menfegol, another cytotoxic spermicide, were evaluated as were several modifications in the base formulation. Menfegol produced essentially the same results as N-9. Altering the base formulation proved to be nonbeneficial because a decrease in the long-term spermicidal effectiveness was obtained. These results suggest that the LASRS suppository has good vehicle properties for the delivery of active ingredients to the vagina.

Participant characteristics associated with withdrawal from a large randomized trial of spermicide effectiveness.

BACKGROUND: In most recent large efficacy trials of barrier contraceptive methods, a high proportion of participants withdrew before the intended end of follow-up. The objective of this analysis was to explore characteristics of participants who failed to complete seven months of planned participation in a trial of spermicide efficacy. METHODS: Trial participants were expected to use the assigned spermicide for contraception for 7 months or until pregnancy occurred. In bivariable and multivariable analyses, we assessed the associations between failure to complete the trial and 17 pre-specified baseline characteristics. In addition, among women who participated for at least 6 weeks, we evaluated the relationships between failure to complete, various features of their first 6 weeks of experience with the spermicide, and characteristics of the study centers and population. RESULTS: Of the 1514 participants in this analysis, 635 (42%) failed to complete the study for reasons other than pregnancy. Women were significantly less likely to complete if they were younger or unmarried, had intercourse at least 8 times per month, or were enrolled at a university center or at a center that enrolled fewer than 4 participants per month. Noncompliance with study procedures in the first 6 weeks was also associated with subsequent early withdrawal, but dissatisfaction with the spermicide was not. However, many participants without these risk factors withdrew early. CONCLUSIONS: Failure to complete is a major problem in barrier method trials that seriously compromises the interpretation of results. Targeting retention efforts at women at high risk for early withdrawal is not likely to address the problem sufficiently.