The Vaginal Microbiota, Bacterial Biofilms and Polymeric Drug-Releasing Vaginal Rings.

The diversity and dynamics of the microbial species populating the human vagina are increasingly understood to play a pivotal role in vaginal health. However, our knowledge about the potential interactions between the vaginal microbiota and vaginally administered drug delivery systems is still rather limited. Several drug-releasing vaginal ring products are currently marketed for hormonal contraception and estrogen replacement therapy, and many others are in preclinical and clinical development for these and other clinical indications.

Polymorphism characterization of segesterone acetate: A comprehensive study using XRPD, FT-IR and Raman spectroscopy.

Segesterone acetate (SA) is a promising and recently approved drug substance used as a contraceptive. SA has two major polymorphic forms, Form I and II. We have shown through indirect analysis that Form I is the more thermodynamically stable polymorphic form at room temperature, however, during the manufacturing process of SA drug products the solid-state stability must be shown to be under control.

The ins and outs of drug-releasing vaginal rings: a literature review of expulsions and removals.

Introduction: There is considerable interest in vaginal ring technology for sustained/controlled administration of drugs to the human vagina. Seven drug-releasing vaginal rings have reached market and other experimental devices are in preclinical/clinical development. Although most women who have used rings are satisfied and find them acceptable, involuntary expulsions and voluntary removals are known to occur and are widely reported.

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).

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.

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.

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.

Solid state C 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 C 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.

Effects of concurrent vaginal miconazole treatment on the absorption and exposure of Nestorone® (segesterone acetate) and ethinyl estradiol delivered from a contraceptive vaginal ring: a randomized, crossover drug-drug interaction study.

Objectives: To evaluate the effects of concurrent administration of three vaginal miconazole nitrate formulations on the absorption and exposure of Nestorone® (segesterone acetate) and ethinyl estradiol from a novel contraceptive vaginal ring (NES/EE CVR).

Study Design: This was an open-label, randomized, crossover, drug-drug interaction study conducted over three menstrual cycles in healthy women with regular menses. We compared systemic exposure to NES and EE by determining area under the curve (AUC) with CVR only and CVR with each miconazole treatment.

Interactions of amidated acids with heparin.

Raman and NMR studies are performed to characterize the solution structures of complexes between heparin and a group of amidated acids, which act as delivery agents that facilitate the gastrointestinal absorption of orally administered heparin. At concentrations typically employed for the oral drug delivery of heparin, the contact points between heparin complexed with the delivery agents include points near the OH groups of heparin. The results suggest that heparin interacts rather nonspecifically with the amidated acids as monomers and with self-associated complexes of the delivery agents.

Physical properties of compounds promoting oral delivery of macromolecular drugs.

The spectroscopic and solution properties of a series of amidated acids (delivery agents), which promote the gastrointestinal absorption of USP heparin and other drugs that show poor oral bioavailability, are investigated using Raman and NMR spectroscopy. The results show evidence for self-association at low concentrations of delivery agents that increases as the concentration of the delivery agent is increased. The self-associate is characterized by ring-ring stacking interactions, and the best geometrical arrangement for the stacking is the parallel-shifted arrangement of the rings.