Progesterone vaginal ring as a new contraceptive option for lactating mothers: Evidence from a multicenter non-randomized comparative clinical trial in India.

OBJECTIVES: Evaluate and compare contraceptive efficacy, safety, continuation rates and duration of lactational amenorrhea (LA) in married lactating women (20-35 years) using the progesterone vaginal ring (PVR) or Copper-T380A intrauterine device (IUD) during the first postpartum year. STUDY DESIGN: We conducted a one-year multicenter, non-randomized, non-inferiority, open-label, comparative trial at 20 centers in India and compared efficacy, safety, continuation and LA plus feeding patterns and growth/well-being of participants' infants. Women used four 3-month PVRs consecutively (lost PVRs were not replaced) and were to breastfeed at least four times/day. We used Pearl Index (PI) and Kaplan Meier (K-M) rates to analyze pregnancy and K-M for continuation. RESULTS: We enrolled 789 women (459 PVR, 330 IUD). Neither PI nor K-M one-year pregnancy rates differed significantly between groups (PI: PVR-0.62; IUD-0.35); (K-M: PVR-0.7; IUD-0.4, p = 0.58). Continuation rates at 12 months were 78.5% (IUD) vs. 56.9% (PVR) (p < 0.001). Ring expulsions and menorrhagia were the most common discontinuation among PVR/IUD users respectively. The median duration of LA among PVR vs. IUD users was 405 vs. 120 days (p < 0.001). Both groups reported similar adverse events (PVR: 24.2%; IUD: 23.0%); there were no serious adverse events among PVR users. Infants from both groups fed 12-7 times/day and grew at expected rates. CONCLUSIONS: Efficacy and safety outcomes were comparable among women in both groups. Continuation rates for PVR, a woman-controlled method, were shorter than IUD rates while PVR users maintained LA significantly longer than IUD users. Infant breastfeeding and growth patterns/well-being were favorable in both groups. IMPLICATIONS: PVR, a user-controlled device, offers an additional contraceptive choice for lactating women for one-year postpartum use and can help to address the unmet need for contraception among postpartum women while encouraging breastfeeding to enhance infant growth and well-being.

Dose-finding study of a 90-day contraceptive vaginal ring releasing estradiol and segesterone acetate.

OBJECTIVE: To evaluate serum estradiol (E2) concentrations during use of 90-day contraceptive vaginal rings releasing E2 75, 100, or 200 mcg/day and segesterone acetate (SA) 200 mcg/day to identify a dose that avoids hypoestrogenism. STUDY DESIGN: We conducted a multicenter dose-finding study in healthy, reproductive-aged women with regular cycles with sequential enrollment to increasing E2 dose groups. We evaluated serum E2 concentrations twice weekly for the primary outcome of median E2 concentrations throughout initial 30-day use (target ≥40 pg/mL). In an optional 2-cycle extension substudy, we randomized participants to 2- or 4-day ring-free intervals per 30-day cycle to evaluate bleeding and spotting based on daily diary information. RESULTS: Sixty-five participants enrolled in E2 75 (n = 22), 100 (n = 21), and 200 (n = 22) mcg/day groups; 35 participated in the substudy. Median serum E2 concentrations in 75 and 100 mcg/day groups were <40 pg/mL. In the 200 mcg/day group, median E2 concentrations peaked on days 4-5 of CVR use at 194 pg/mL (range 114-312 pg/mL) and remained >40 pg/mL throughout 30 days; E2 concentrations were 37 pg/mL (range 28-62 pg/mL) on days 88-90 (n = 11). Among the E2 200 mcg/day substudy participants, all had withdrawal bleeding following ring removal. The 2-day ring-free interval group reported zero median unscheduled bleeding and two (range 0-16) and three (range 0-19) unscheduled spotting days in extension cycles 1 and 2, respectively. The 4-day ring-free interval group reported zero median unscheduled bleeding or spotting days. CONCLUSIONS: Estradiol concentrations with rings releasing E2 200 mcg/day and SA 200 mcg/day avoid hypoestrogenism over 30-day use. IMPLICATIONS: A 90-day contraceptive vaginal ring releasing estradiol 200 mcg/day and segesterone acetate 200 mcg/day achieves estradiol concentrations that should avoid hypoestrogenism and effectively suppresses ovulation.

In vitro release testing methods for drug-releasing vaginal rings.

Drug-releasing vaginal rings are torus-shaped devices, generally fabricated from thermoplastic polymers or silicone elastomers, used to administer pharmaceutical drugs to the human vagina for periods typically ranging from three weeks to twelve months. One of the most important product performance tests for vaginal rings is the in vitro release test. Although it has been fifty years since a vaginal ring device was first described in the scientific literature, and despite seven drug-releasing vaginal rings having been approved for market, there is no universally accepted method for testing in vitro drug release, and only one non-compendial shaking incubator method (for the estradiol-releasing ring Estring®) is described in the US Food and Drug Administration's Dissolution Methods Database. Here, for the first time, we critically review the diverse range of test methods that have been described in the scientific literature for testing in vitro release of drug-releasing vaginal rings. Issues around in vitro-in vivo correlation and modelling of in vitro release data are also discussed.

Post-use ring weight and residual drug content as potential objective measures of user adherence to a contraceptive progesterone vaginal ring.

OBJECTIVES: The primary aim was to investigate post-use ring weight as a potential measure of cumulative adherence to a progesterone-releasing vaginal ring. STUDY DESIGN: We weighed and quantified residual progesterone in 115 vaginal rings following 90-day use by participants in an acceptability trial conducted in Nigeria, Senegal and Kenya. The primary objective was to correlate residual progesterone content with post-use ring weight. Secondary objectives included correlating ring weight with putative duration of ring use, and, where participants used two rings consecutively in the study, correlating residual content between these paired rings. RESULTS: Mean ring weight and progesterone content of used rings was 8.62±0.24 g and 1245±245 mg respectively, versus 9.37±0.02 and 2058±21 mg for control rings. Most used rings (90.4%) had residual progesterone levels less than 85% of the nominal loading. Linear regression showed a strong positive linear trend between residual progesterone content and post-use ring weight for all rings (r2=0.82). Duration of ring use was inversely associated (p=.00020) with ring weight. CONCLUSIONS: Post-use ring weight is highly correlated with residual progesterone content, a benchmark objective cumulative measure of adherence, and thus potentially useful as a surrogate objective measure of cumulative adherence to a progesterone-releasing vaginal ring. IMPLICATION STATEMENT: For vaginal rings containing a high initial drug loading and releasing a relatively large fraction of the initial loading during clinical use, post-use ring weight may offer a simple and inexpensive alternative to residual content testing for accurate monitoring of user adherence.

Solid state 13C NMR spectroscopy provides direct evidence for reaction between ethinyl estradiol and a silicone elastomer vaginal ring drug delivery system.

Steroid molecules have a long history of incorporation into silicone elastomer materials for controlled release drug delivery applications. Previously, based on in vitro release testing and drug content analysis, we demonstrated indirectly that the contraceptive progestin levonorgestrel (LNG) chemically and irreversibly binds to addition cure silicone elastomers, presumably via a hydrosilylation reaction between the levonorgestrel ethynyl group and the hydrosilane groups in the poly(dimethylsiloxane-co-methylhydrosiloxane) crosslinker of the silicone elastomer. Here, for the first time, we report that solid state 13C nuclear magnetic resonance (NMR) spectroscopy provides direct evidence for the irreversible binding of ethinyl estradiol (EE) - an estrogenic steroid molecule also containing an ethynyl functional group - to an addition cure silicone elastomer. By preparing silicone elastomer samples containing 13C-labelled EE, signals in the NMR spectra could readily be assigned to both the free and bound EE. Additional depolymerisation studies, performed on an addition cure silicone elastomer system from which the unbound EE fraction was completely extracted, further confirmed the presence of bound EE through the formation of coloured reaction mixtures resulting from the reaction of bound EE and trifluoroacetic acid (TFA). These methods will be particularly useful in the ongoing development of new steroid-releasing silicone drug delivery devices, including various vaginal ring devices for contraception, HIV prevention and multipurpose prevention technology applications.