Release behavior of copper ion in a novel contraceptive composite

Recent progress in advanced biomaterials for long-acting reversible contraception

Unintended pregnancy is a global issue with serious ramifications for women, their families, and society, including abortion, infertility, and maternal death. Although existing contraceptive strategies have been widely used in people's lives, there have not been satisfactory feedbacks due to low contraceptive efficacy and related side effects (e.g., decreased sexuality, menstrual cycle disorder, and even lifelong infertility). In recent years, biomaterials-based long-acting reversible contraception has received increasing attention from the viewpoint of fundamental research and practical applications mainly owing to improved delivery routes and controlled drug delivery. This review summarizes recent progress in advanced biomaterials for long-acting reversible contraception via various delivery routes, including subcutaneous implant, transdermal patch, oral administration, vaginal ring, intrauterine device, fallopian tube occlusion, vas deferens contraception, and Intravenous administration. In addition, biomaterials, especially nanomaterials, still need to be improved and prospects for the future in contraception are mentioned.

Feasibility evaluation of a Cu-38 Zn alloy for intrauterine devices: In vitro and in vivo studies

The existing adverse effects of copper in copper-containing intrauterine devices (Cu-IUDs) have raised concerns regarding their use. These adverse effects include burst release of cupric ions (Cu²⁺) at the initial stage and an increasingly rough surface of the Cu-IUDs. In this study, we investigated the use of two copper alloys, Cu-38 Zn and H62 as the new upgrading or alternative material for IUDs. Their corrosive properties were studied in simulated uterine fluid (SUF) by using electrochemical methods, with pure Cu as a control. We studied the in vitro long-term corrosion behaviors in SUF, cytotoxicity to uterine cells (human endometrial epithelial cells and human endometrial stromal cells), in vivo biocompatibility and contraceptive efficacy of pure Cu, H62, and Cu-38 Zn. In the first month, the burst release rate of Cu²⁺ in the Cu-38 Zn group was significantly lower than those in the pure Cu and H62 groups. The in vitro cytocompatibility Cu-38 Zn was better than that of pure Cu and H62. Moreover, Cu-38 Zn showed improved tissue biocompatibility in vivo experiments. Therefore, the contraceptive efficacy of the Cu-38 Zn is still maintained as high as the pure Cu while the adverse effects are significantly eased, suggesting that Cu-38 Zn can be a suitable potential candidate material for IUDs. STATEMENT OF SIGNIFICANCE: The existing adverse effects associated with the intrinsic properties of copper materials for copper-containing intrauterine devices (Cu-IUD) are of concern in their employment. Such as, burst release of cupric ions (Cu²⁺) at the initial stage and an increasingly rough surface of the Cu-IUD. In this work, Cu alloyed with a high amount of bioactive Zn was used for a Cu-IUD. The Cu-38 Zn alloy exhibited reduced burst release of Cu²⁺ within the first month compared with the pure Cu and H62. Furthermore, the Cu-38 Zn alloy displayed significantly improved biocompatibility and a much smoother surface. Therefore, high antifertility efficacy of the Cu-38 Zn alloy was well maintained, while the adverse effects are significantly eased, suggesting that the Cu-38 Zn alloy is promising for a Cu-IUD.

Green synthesis of a plant-derived protein protected copper quantum cluster for intrauterine device application

Fluorescent copper quantum clusters (CuQCs) have received great interest in recent times due to their attractive features, such as water solubility, low cost, wide availability of Cu and good biocompatibility. Recently, considerable efforts have been devoted to the preparation and applications of CuQCs. Herein, we report a simple one-pot green method for the preparation of fluorescent CuQCs using a plant-derived protein, gluten, as a stabilizing agent. Gluten, a naturally abundant, low-cost and sustainable plant-protein derived from wheat, was employed both as a reducing and stabilizing agent to produce blue emitting CuQCs. The CuQCs were characterized by UV-Vis absorption, fluorescence, FT-IR, TEM, and XPS. We further incorporated CuQCs into a polymer to study the release rate of Cu2+ ions from a CuQC-polymer composite, since copper ions are well known for their fungicidal properties and contraceptive action in copper-T (CuT). The CuQCs were incorporated into a model polymer, polyurethane (PU), by melt compounding, and the mixtures were extruded in the form of a wire. It was observed that the CuQCs were uniformly dispersed within the polymer matrix. An in vitro experiment was carried out to quantify the potential release of Cu(ii) ions for contraceptive applications. The developed nanocomposite releases Cu(ii) ions for 90 days, which suggests the potential application of the CuQCs in the medical field like the development of short-term intrauterine devices (IUDs). Compared to conventional IUDs, here the CuQC-PU nanocomposite reduces the burst release of the Cu2+, and the release rates can be tuned by changing the composition of the materials. These results suggest that the CuQC-PU nanocomposites have great potential to replace current commercial intrauterine devices.

New developments in intrauterine device use: focus on the US

Many more women in the US today rely upon intrauterine devices (IUDs) than in the past. This increased utilization may have substantially contributed to the decline in the percentage of unintended pregnancies in the US. Evidence-based practices have increased the number of women who are medically eligible for IUDs and have enabled more rapid access to the methods. Many women enjoy freedom to use IUDs without cost, but for many the impact of the Affordable Care Act has yet to be realized. Currently, there are three hormonal IUDs and one copper IUD available in the US. Each IUD is extremely effective, convenient, and safe. The newer IUDs have been tested in populations not usually included in clinical trials and provide reassuring answers to older concerns about IUD use in these women, including information about expulsion, infection, and discontinuation. On the other hand, larger surveillance studies have provided new estimates about the risks of complications such as perforation, especially in postpartum and breastfeeding women. This article summarizes significant features of each IUD and provides a summary of the differences to aid clinicians in the US and other countries in advising women about IUD choices.

State-of-the-art of non-hormonal methods of contraception: III. Intrauterine devices

Since the 1959 revival of the IUD, non-hormonal devices have become the most widely used of all reversible contraceptives. Pregnancy rates of copper-releasing IUDs in current use range from approximately 0.5 to 1.5 per hundred continuing users in the first year, with somewhat lower annual pregnancy rates thereafter. Evidence-based research has been systematically conducted and translated into guidelines for eligibility criteria and problem management. Recent device research, beyond the T, Multiload and frameless devices has centred on improved designs such as U ,Y and Slimline shapes, or enhanced copper release, the latter through electrochemical effects or nanotechnology applications. Other IUD research foci concern devices that decrease bleeding and pain by releasing non-steroidal anti-inflammatory drugs. Yet other research lines indicate noncontraceptive benefits of copper intrauterine devices in protecting against endometrial cancer, and favourable risk-benefit analyses of IUD use by women at risk of or post HIV infection. IUD mechanisms of action and the relation of IUDs to pelvic infection and ectopic pregnancy are briefly reviewed. For our literature search we used Medline, Popline and Cochrane Library data bases, Google search, our personal files, and the references contained in articles in our files.

Effective inhibition of the early copper ion burst release with ultra-fine grained copper and single crystal copper for intrauterine device application

To solve the main problems of existing coarse grained copper (CG Cu) intrauterine devices (IUD)-namely burst release and a low transfer efficiency of the cupric ions during usage-ultra-fine grained copper (UFG Cu) and single crystal copper (SC Cu) have been investigated as potential substitutes. Their corrosion properties with CG Cu as a control have been studied in simulated uterine fluid (SUF) under different conditions using electrochemical measurement methods. Long-term immersion of UFG Cu, SC Cu and CG Cu samples in SUF at 37 °C have been studied for 300 days. A lower copper ion burst release and a higher efficiency release of cupric ions were observed for UFG Cu and SC Cu compared with CG Cu in the first month of immersion and 2 months later. The respective corrosion mechanisms for UFG Cu, SC Cu and CG Cu in SUF are proposed. In vitro biocompatibility tests show a better cellular response to UFG Cu and SC Cu than CG Cu. In terms of instantaneous corrosion behavior, long-term corrosion performance and in vitro biocompatibility, the three pure copper materials follow the order: UFG Cu>SC Cu>CG Cu, which indicates that UFG Cu could be the most suitable candidate material for intrauterine devices.

The contraceptive effect of a novel filtering-type nano-copper complex/polymer composites intra-vas device on male animals

Contraceptive techniques which target vas deferens have been paid great attention for their good efficacy, safety and reversibility. We have made a filtering-type intra-vas device (IVD) using nano-copper complex/polymer composites. Twenty male adult Beagle dogs and 40 male rabbits were randomly assigned to four groups (sham-operation, IVD, reversal and vasectomy groups). Dogs' semen parameters, concentration of α-glucosidase, copper and zinc ions were tested pre-operation and 1, 3, 6 and 12 months post-operation. The pregnancy rates of the rabbits were evaluated by mating trials after the IVDs were implanted. The histology of testis, epididymides and vas deferens of the animals was examined using an electron microscope. Apoptosis of the cells in the testes, epididymides and vas deferens was detected by TUNEL method. There was no sperm in the semen of dogs, which had been inserted IVD and vasectomized at 1, 3, 6 and 12 months post-operation. The concentration of α-glucosidase in the IVD group, reversal group and sham-operation group was not significantly different between pre- and post-operation. The pregnancy rates of the female rabbits in the vasectomy, IVD and reversal groups were all zero, but the pregnancy rate in the reversal group, after taking out IVD, and that of the sham-operation group was 60% and 80%, respectively. The ultrastructures of the testes, epididymides and vas deferens of the male animals in the IVD group and sham-operation group were in normal ranges compared with the vasectomy group. The apoptosis of the cells in the testes, epididymides and vas deferens in the vasectomy group of both dogs and rabbits was obvious compared with the other groups. No significant changes in the quantities of copper and zinc ions were found in semen of the male dogs both pre- and post-operation. Our studies demonstrated that the filtering-type nano-copper complex/polymer composites intra-vas device may be an efficacious, safe and reversible male contraceptive device.

Initial studies on a novel filtering-type intra-vas device in male dogs

BACKGROUND

To relieve the side effects induced by the complete obstruction of the vas deferens, we created a filtering-type intra-vas device (IVD) which is made of materials composed of nano-SiO(2)-copper complex cross-linking polymer composites.

STUDY DESIGN

Eight male beagle dogs were grouped into nonimplanted control group and IVD-implanted group. We tested the efficacy of the sperm filtering effect of the new IVD material for 12 months and examined the influence of the IVD materials on the cells of the vas deferens, epididymis and testis.

RESULTS

The densities of sperm were reduced significantly after the IVD was implanted; no motile sperm were found after the third month. No obvious morphological changes were found in the cells of the vas deferens, epididymis and testis in the IVD-implanted group.

CONCLUSIONS

The filtering-type nano-SiO(2)-copper complex/polymer composite IVD is able to filter the sperm of the male dogs, and the IVD material did not cause obvious damage to the cells of the male reproductive organs after 1 year of implantation.