Long-acting reversible contraception by effervescent microneedle patch

MXenes-integrated microneedle combined with asiaticoside to penetrate the cuticle for treatment of diabetic foot ulcer

Patients with diabetic foot ulcers usually suffer from inefficient epithelisation and angiogenesis accompanied by chronic wound healing. Diabetic foot ulcers remain a major challenge in clinical medicine; however, traditional treatments are incapable of transdermal drug delivery, resulting in a low drug delivery rate. We report the development of Ti2C3 MXenes-integrated poly-γ-glutamic acid (γ-PGA) hydrogel microneedles to release asiaticoside (MN-MXenes-AS). Asiaticoside was loaded into PGA-MXenes hydrogel to facilitate cell proliferation while regulating angiogenesis. The characterisation and mechanical strength of the microneedles were investigated in vitro, and the wound-healing efficacy of the microneedles was confirmed in diabetic mice. MXenes significantly improved the mechanical strength of microneedles, while γ-PGA hydrogels provided a moist microenvironment for wound healing. Mice treated with MN-MXenes-AS demonstrated obvious improvements in wound healing process. We successfully fabricated an MXenes-integrated microneedle that possesses sufficient rigidity to penetrate the cuticle for subcutaneous drug delivery, thereby accelerating diabetic wound healing. We demonstrated that MN-MXenes-AS is effective in promoting growth both in vivo and in vitro. Collectively, our data show that MN-MXenes-AS accelerated the healing of diabetic foot ulcers, supporting the use of these microneedles in the treatment of chronic wounds.

Graphical Abstract

Synergistically Detachable Microneedle Dressing for Programmed Treatment of Chronic Wounds

Chronic wounds such as diabetic feet undergo a lifetime risk of developing into incurable ulcers. Current treatments for chronic wounds remain unsatisfactory due to the lack of ideal wound dressings that integrate facile dressing change, long-acting treatment, and high therapeutic efficacy into one system. Herein, a synergistically detachable microneedle (MN) dressing with a dual-layer structure is presented to enable programmed treatment via one-time dressing application. Such a dual-layer dressing MN system (DDMNS) is composed of chitosan (CS) hydrogel dressing (CSHD) on top of a detachable MN patch with a CS tip and a polyvinyl pyrrolidone (PVP) backing substrate incorporated with magnesium (Mg). The synergistic detachment is achieved with the backing Mg/PVP substrate dissolving within minutes due to the local moist environment of the CSHD enhancing the reaction between Mg and inflammation microenvironment. The combined treatment of Mg and panax notoginseng saponins (PNS) loaded in DDMNS achieves antibacterial, neovascularization, and activating a benign immune response so that the three overlapping periods of the inflammation, tissue proliferation, and tissue remodeling of wound healing reach a dynamic balance. This advanced DDMNS provides a facile approach for the programmed treatment of chronic wound management indicating potential value in wound healing and other related biomedical fields.

Smart Mushroom-Inspired Imprintable and Lightly Detachable (MILD) Microneedle Patterns for Effective COVID-19 Vaccination and Decentralized Information Storage

The key to controlling the spread of the coronavirus disease 2019 (COVID-19) and reducing mortality is highly dependent on the safe and effective use of vaccines for the general population. Current COVID-19 vaccination practices (intramuscular injection of solution-based vaccines) are limited by heavy reliance on medical professionals, poor compliance, and laborious vaccination recording procedures, resulting in a waste of health resources and low vaccination coverage, etc. In this study, we developed a smart mushroom-inspired imprintable and lightly detachable (MILD) microneedle platform for the effective and convenient delivery of multidose COVID-19 vaccines and decentralized vaccine information storage. The mushroom-like structure allows the MILD system to be easily pressed into the skin and detached from the patch base, acting as a "tattoo" to record the vaccine counts in situ without any storage equipment, offering quick accessibility and effortless readout, saving a great deal of valuable time and energy for both patients and health professionals. After loading inactivated SARS-CoV-2 virus-based vaccines, MILD system induced a high level of antibodies against the SARS-CoV-2 receptor-binding domain (RBD) in vivo without eliciting systemic toxicity and local damage. Collectively, this smart delivery platform serves as a promising carrier to improve COVID-19 vaccination efficacy through its dual capabilities of vaccine delivery and in situ data storage, thus exhibiting great potential for helping to contain the COVID-19 pandemic or a resurgence.

Restorative biodegradable two-layered hybrid microneedles for melanoma photothermal/chemo co-therapy and wound healing

Tumor killing and wound healing are two complementary and influential processes during the treatment of melanoma. Herein, a two-layered microneedle platform was developed with bifunctional effect of chemo-photothermal synergistic melanoma therapy and skin regeneration. The bifunctional platform composed of embeddable curcumin nanodrugs/new Indocyanine Green/hyaluronic acid (Cur NDs/IR820/HA) microneedles and sodium alginate/gelatin/hyaluronic acid (SA/Ge/HA) supporting backing layer was prepared through a two-step casting process. With uniform incorporation of curcumin nanodrugs and IR820, the microneedles exhibited excellent photothermal performance under external near-infrared (NIR) light stimulation and tumor co-therapy ability. Once the embeddable microneedles were inserted into skin, they would rapidly dissolve and activate drug release successfully for tumor treatment. Moreover, the SA/Ge/HA supporting backing layer was left behind to cover the wound and promote the proliferation of endothelial and fibroblasts cells for enhanced skin regeneration. The two-layered microneedles platform can simultaneously eliminate the tumor and accelerate wounding healing, which may be potentially employed as a competitive strategy for the treatment of melanoma.

Core-shell microneedle patch for six-month controlled-release contraceptive delivery

There is a tremendous need for simple-to-administer, long-acting contraception, which can increase access to improved family planning. Microneedle (MN) patches enable simple self-administration and have previously been formulated for 1-2 months' controlled release of contraceptive hormone using monolithic polymer/drug MN designs having first-order release kinetics. To achieve zero-order release, we developed a novel core-shell MN patch where the shell acts as a rate-controlling membrane to delay release of a contraceptive hormone, levonorgestrel (LNG), for 6 months. In this approach, LNG was encapsulated in a poly(lactide-co-glycolide) (PLGA) core surrounded by a poly(l-lactide) (PLLA) shell and a poly(D,l-lactide) (PLA) cap that were fabricated by sequential casting into a MN mold. Upon application to skin, the core-shell MNs utilized an effervescent interface to separate from the patch backing within 1 min. The core-shell design limited the initial 24 h burst release of LNG to 5.8 ± 0.5% and achieved roughly zero-order LNG release for 6.2 ± 0.1 months in vitro. A monolithic MN patch formulated with the same LNG and PLGA core, but without the rate-controlling PLLA shell and PLA cap had a larger LNG burst release of 22.6 ± 2.0% and achieved LNG release for just 2.1 ± 0.2 months. This study provides the first core-shell MN patch for controlled months-long drug release and supports the development of long-acting contraception using a simple-to-administer, twice-per-year MN patch.

Long-acting microneedle patch loaded with adipose collagen fragment for preventing the skin photoaging in mice

Skin photoaging is one of the most serious public health problems in the 21st century that may lead to thin, saggy, and structurally weakened skin. Adipokine therapy toward skin photoaging is always associated with poor permeability, biologic stability and the short in vivo release duration. Our laboratory previously extracted an extracellular matrix component of adipose tissue by purely physical methods, namely "adipose collagen fragment (ACF)", which holds promise for preventing skin photoaging. However, the injection treatment of ACF requires repeated preparation processes and injection procedures, which may be time-consuming and painful. Therefore, we describe the fabrication and assessment of a detachable ACF-microneedle (ACF-MN) patch that creates minimally invasive dermal microtrauma upon application. And we evaluated the morphology characterization, mechanical properties and puncture performance in vitro. The delivery efficiency of ACF from the patches was estimated in vitro and vivo. Then, the therapeutic efficacy was identified through applying ACF-MN patches into the dermis of UVA-induced photoaging mice and the related detection of skin photoaging was estimated. Our results demonstrated that ACF-MN exhibited well skin puncture performance and could release ACF component slowly. Meanwhile, this microneedle device loaded with ACF exhibited the treatment efficiency on skin photoaging in a mouse model. Therefore, implantation of the microtrauma-mediated, long-acting ACF-MN system can be utilized as a potential candidate for preventing skin photoaging in the clinic.

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.

Women's preferences and acceptance for different drug delivery routes and products

To use or not to use, that is the first decision to take regarding a drug product. This mandatory step for adherence dictates product efficacy. The determinants for such decision do not only rely on the priority of the therapeutic or preventive strategy, but are related to a complex network of perceptions, preferences, personal and cultural backgrounds, and results from previous experiences. Women's preferences for dosage forms and even for drug delivery routes have been mainly studied in the fields of contraception and HIV prevention (and their related multipurpose approaches). Much less attention has been devoted to other therapeutic or preventive strategies. In a time when patient-centred approaches and shared decisions are increasingly valued, considering women's preferences and their main determinants is essential for product development and selection. Such products will be more likely to be chosen and used as intended, increasing efficacy, and reducing the overall costs related with these treatments. This knowledge shall be integrated in early stages of product development. This article reviews the state of the art related with women's preferences and acceptance for different dosage forms and drug delivery routes involved in women's health. The methodologies used for collecting these data and their major drawbacks are discussed. Results obtained from acceptability studies and the main determinants for selection of preventive and treatment drug products are discussed as tools for new developments in the field.

Recent Advances of Microneedles and Their Application in Disease Treatment

For decades, scientists have been doing a lot of research and exploration to find effective long-term analgesic and/or disease-modifying treatments. Microneedles (MNs) are a simple, effective, and painless transdermal drug delivery technology that has emerged in recent years, and exhibits great promise for realizing intelligent drug delivery. With the development of materials science and fabrication technology, the MN transdermal drug delivery technology has been applied and popularized in more and more fields, including chronic illnesses such as arthritis or diabetes, cancer, dermatocosmetology, family planning, and epidemic disease prevention, and has made fruitful achievements. This paper mainly reviews the latest research status of MNs and their fabrication methodology, and summarizes the application of MNs in the treatment of various diseases, as well as the potential to use nanotechnology to develop more intelligent MNs-based drug delivery systems.

How Protein Methylation Regulates Steroid Receptor Function

Steroid receptors (SRs) are members of the nuclear hormonal receptor family, many of which are transcription factors regulated by ligand binding. SRs regulate various human physiological functions essential for maintenance of vital biological pathways, including development, reproduction, and metabolic homeostasis. In addition, aberrant expression of SRs or dysregulation of their signaling has been observed in a wide variety of pathologies. SR activity is tightly and finely controlled by post-translational modifications (PTMs) targeting the receptors and/or their coregulators. Whereas major attention has been focused on phosphorylation, growing evidence shows that methylation is also an important regulator of SRs. Interestingly, the protein methyltransferases depositing methyl marks are involved in many functions, from development to adult life. They have also been associated with pathologies such as inflammation, as well as cardiovascular and neuronal disorders, and cancer. This article provides an overview of SR methylation/demethylation events, along with their functional effects and biological consequences. An in-depth understanding of the landscape of these methylation events could provide new information on SR regulation in physiology, as well as promising perspectives for the development of new therapeutic strategies, illustrated by the specific inhibitors of protein methyltransferases that are currently available.

Silk fibroin double-layer microneedles for the encapsulation and controlled release of triptorelin

A double-layer silk fibroin microneedles (SF-MNs) was proposed for the transdermal delivery of triptorelin. Two-step pouring and centrifugation were employed to prepare SF-MNs. Triptorelin was wrapped in MNs in the form of microcrystals with a size of ∼1 μm. β-sheet nanocrystals (the secondary structure of silk fibroin) were adjusted in content by methanol-vapor treatment to manipulate the characteristics of SF-MNs prepared with two concentrations of silk fibroin. The mechanical strength of MNs was measured and analyzed in proportion to the β-sheet content. The triptorelin in MNs could be released sustainedly in phosphate-buffered saline for 168 h, and the release amount decreased with increasing β-sheet content. The Ritger-Peppas equation was employed to fit the release data. A linear decreasing relationship was observed between the diffusion coefficient and increased β-sheet content. After administration to rats, SF-MNs exhibited long-term testosterone inhibition and maintained castration levels for ≥7 d. Manipulable mechanical properties and release behavior combined with biocompatibility and biodegradability render SF-MNs as viable long-term transdermal delivery devices for triptorelin.

Detachable dissolvable microneedles: intra-epidermal and intradermal diffusion, effect on skin surface, and application in hyperpigmentation treatment

Delivering bioactive compounds into skin tissue has long been a challenge. Using ex vivo porcine and rat skins, here we demonstrate that a detachable dissolvable microneedle (DDMN) array, a special dissolvable microneedle that allows needle detachment from the base within 2 min post administration, can effectively embed a model compound into epidermis and dermis. Diffusion of the compound from the needle embedding sites to the nearby skin tissue is demonstrated at various post administration periods. The relationship between the time that a conventional dissolvable microneedle array is left on skin without needle detachment from the base and the degree of skin surface abrasion at each microneedle penetration spot is also demonstrated on skin of human volunteers. Co-loading glutathione with vitamin C (vitC) can stabilize vitC in the DDMN. DDMN loaded with vitC and glutathione can help erasing post-acne-hyperpigmentation spots.

Microneedle-mediated transdermal nanodelivery systems: a review

The greatest limitation in the development of transdermal drug delivery systems is that only a few drugs can permeate the skin due to the barrier function of the stratum corneum. Active and passive methods are generally available for improving the ability of drug transdermal delivery. However, nanoparticles, as a passive approach, exhibit capacity-constrained permeation enhancement. Thus, microneedle-mediated nanoparticles possess enormous potential and broad prospects. Microneedles promote the penetration of macromolecules by creating microchannels on the skin surface. In this review, the prevailing subknowledge on microneedles (mechanism, classification, and applications of microneedles combined with nanoparticles) is discussed to provide a guideline for readers and a basic reference for further in-depth studies of this novel drug delivery system.

Models and methods to characterise levonorgestrel release from intradermally administered contraceptives

Microneedle (MN)-based technologies have been proposed as a means to facilitate minimally invasive sustained delivery of long-acting hormonal contraceptives into the skin. Intradermal administration is a new route of delivery for these contraceptives and therefore no established laboratory methods or experimental models are available to predict dermal drug release and pharmacokinetics from candidate MN formulations. This study evaluates an in vitro release (IVR) medium and a medium supplemented with ex vivo human skin homogenate (SH) as potential laboratory models to investigate the dermal release characteristics of one such hormonal contraceptive that is being tested for MN delivery, levonorgestrel (LNG), and provides details of an accompanying novel two-step liquid–liquid drug extraction procedure and sensitive reversed-phase HPLC–UV assay. The extraction efficiency of LNG was 91.7 ± 3.06% from IVR medium and 84.6 ± 1.6% from the medium supplemented with SH. The HPLC–UV methodology had a limit of quantification of 0.005 µg/mL and linearity between 0.005 and 25 µg/mL. Extraction and detection methods for LNG were exemplified in both models using the well-characterised, commercially available sustained-release implant (Jadelle®). Sustained LNG release from the implant was detected in both media over 28 days. This study reports for the first time the use of biologically relevant release models and a rapid, reliable and sensitive methodology to determine release characteristics of LNG from intradermally administered long-acting drug delivery systems.

Human-centred design of a new microneedle-based hormonal contraceptive delivery system

Background: It is estimated that 225 million women worldwide have an unmet need for family planning, and more than half live in low- and middle-income countries. Increasing the choice of contraceptive methods available can reduce this unmet need. Microneedle drug delivery systems represent a new technology for minimally invasive self-administration of contraceptives. We explored stakeholders’ views on different aspects of a proposed microneedle-based hormonal contraceptive delivery system. The feedback was used to iteratively develop this delivery system.

Methods: Focus group discussions and semi-structured interviews were conducted with potential stakeholders (women and trans males of childbearing age, their partners, and health professionals and organisations that provide family planning advice and contraception services) in Uganda, The Gambia, Malawi, and the UK, exploring concept acceptability and gathering feedback on different aspects of design and usability of the proposed delivery system.

Results: Participants viewed the concept of a new, microneedle-based contraceptive favourably. In Uganda, participants were presented with 7 different prototype applicators and identified desirable features of a preferred delivery device; their input reducing the number of prototypes that were subsequently evaluated by stakeholders in The Gambia and the UK. Participants in these countries helped to identify and/or confirm the most desirable characteristics of the applicator, resulting in design consolidation into a refined concept applicator. The final, optimised applicator prototype was validated during user research in Malawi. This human-centred design approach was also used to iteratively develop an information leaflet for the device. During these user studies, other preferred aspects of a contraceptive delivery system were also evaluated, such as anatomical site of application, duration of action, and return to fertility.

Conclusions: A new microneedle-based contraceptive delivery system was iteratively developed using a human-centred design approach and was favourably received by potential stakeholders. The product is now being refined for testing in pre-clinical studies.

A Colorimetric Dermal Tattoo Biosensor Fabricated by Microneedle Patch for Multiplexed Detection of Health-Related Biomarkers

Detection of biomarkers associated with body conditions provides in-depth healthcare information and benefits to disease management, where the key challenge is to develop a minimally invasive platform with the ability to directly detect multiple biomarkers in body fluid. Dermal tattoo biosensor holds the potential to simultaneously detect multiple health-related biomarkers in skin interstitial fluid because of the features of minimal invasion, easy operation, and equipment-free result reading. Herein, a colorimetric dermal tattoo biosensor fabricated by a four-area segmented microneedle patch is developed for multiplexed detection of health-related biomarkers. The biosensor exhibits color changes in response to the change of biomarker concentration (i.e., pH, glucose, uric acid, and temperature), which can be directly read by naked eyes or captured by a camera for semi-quantitative measurement. It is demonstrated that the colorimetric dermal tattoo biosensor can simultaneously detect multiple biomarkers in vitro, ex vivo, and in vivo, and monitor the changes of the biomarker concentration for at least 4 days, showing its great potential for long-term health monitoring.

Contraceptive technology research & development: a call for inclusion of trans and gender diverse individuals assigned female at birth

OBJECTIVE

Increased research efforts over the past decade provide a more in-depth understanding of the diverse fertility desires and family planning needs of trans and gender diverse individuals assigned female at birth (TGD AFAB). Despite this increased understanding and unmet need, global health researchers and contraceptive product developers have yet to include TGD AFAB individuals and considerations of their needs in the product development process, marginalising this historically underrepresented population. The aim of this perspective is to present the case for inclusion of TGD AFAB individuals in contraceptive research.

MAIN OUTCOMES

This perspective summarises the most recent literature characterising contraceptive access and use within TGD AFAB populations as well as the barriers to use. Furthermore, this perspective offers insight into how novel contraceptive technologies in the research and development pipeline could potentially appeal to TGD AFAB populations and recommends steps product developers can make towards being more inclusive.

CONCLUSIONS

With current research efforts in contraceptive product development aimed at expanding the method mix to appeal to a more diverse population of potential users, it behoves product developers to be more inclusive of TGD AFAB individuals in the development process and consider them as stakeholders of an expanded contraceptive method mix.

Systematic comparisons of dissolving and swelling hyaluronic acid microneedles in transdermal drug delivery

Transdermal drug delivery efficacy of hyaluronic acid dissolving microneedles (HA DMNs) is limited by low loading dose and poor drug condensation in needles. HA swelling MNs (HA SMNs) could improve the efficacy, but comparisons between the formulations is missing. In this work, DMNs and SMNs were fabricated of HA and methacrylated HA, respectively. Their properties of transdermal drug delivery were systematically compared. HA SMNs exhibited enhanced mechanical strength, fast swelling performance, and extended duration of microchannels in skin. The doxorubicin (DOX) loaded by one-step loading protocol in needles and baseplate of SMNs could be transdermally delivered through the diffusing path mediated by swollen needles, conquering the limit of poor drug condensation in DMNs needles and generated a longer Tmax but higher Cmax. The relative bioavailability of DOX/SMNs towards DOX/DMNs was 200% within 12 h. The results provide theoretical references for the application of HA MNs mediated transdermal drug delivery.

Conformable microneedle pH sensors via the integration of two different siloxane polymers for mapping peripheral artery disease

Flexible microneedles are important tools that allow access to the inside of biological tissue from the outside without surgery. However, it had been hard to realize microneedle sensor arrays on flexible substrates because of the difficulty of attaining a needle with a high Young’s modulus for a selected area on a thin or soft substrate. In this work, we developed a microneedle sensor on a hybrid substrate based on high Young’s modulus epoxy siloxane for the microneedles and low Young’s modulus polydimethylsiloxane for the conformable substrate. Polyaniline was deposited on the microneedle for pH sensing. The mechanical durability of the device was assessed by insertion into pig skin 1000 times. Last, the flexible microneedle pH sensors showed their utility for monitoring pH distribution in rats in a peripheral artery diseases model.

Multifunctional Magnesium Organic Framework-Based Microneedle Patch for Accelerating Diabetic Wound Healing

Diabetic wound healing is one of the major challenges in the biomedical fields. The conventional single drug treatments have unsatisfactory efficacy, and the drug delivery effectiveness is restricted by the penetration depth. Herein, we develop a magnesium organic framework-based microneedle patch (denoted as MN-MOF-GO-Ag) that can realize transdermal delivery and combination therapy for diabetic wound healing. Multifunctional magnesium organic frameworks (Mg-MOFs) are mixed with poly(γ-glutamic acid) (γ-PGA) hydrogel and loaded into the tips of MN-MOF-GO-Ag, which slowly releases Mg²⁺ and gallic acid in the deep layer of the dermis. The released Mg²⁺ induces cell migration and endothelial tubulogenesis, while gallic acid, a reactive oxygen species-scavenger, promotes antioxidation. Besides, the backing layer of MN-MOF-GO-Ag is made of γ-PGA hydrogel and graphene oxide-silver nanocomposites (GO-Ag) which further enables excellent antibacterial effects for accelerating wound healing. The therapeutic effects of MN-MOF-GO-Ag on wound healing are demonstrated with the full-thickness cutaneous wounds of a diabetic mouse model. The significant improvement of wound healing is achieved for mice treated with MN-MOF-GO-Ag.

Microneedle patch designs to increase dose administered to human subjects

Microneedle (MN) patches are being developed for many different kinds of drugs, but are often limited to delivering sub-milligram doses. This is because larger patches can be more difficult to apply to the skin, and acceptability of larger MN patches by human subjects has received limited study. Here, we fabricated 18 different large MN patch designs by laser microfabrication with different MN length (800-1500 μm), number of MNs (225 to 900 MNs per patch), space between MNs (600-1100 μm), and MN base diameter (200-250 μm). After manual application of these patches to human participants, we assessed dose delivery efficiency, total dose delivered, dose delivered per MN, depth of MN penetration and whole-MN delivery efficiency. We found that all of these parameters generally increased with decreased MN length, increased number of MNs (among those ≤1000 μm in length) and increased MN-MN spacing. All MN patch designs caused less pain than a pin prick sensation and were generally considered acceptable by the study participants. The MN patches induced mild, or sometimes moderate, transient erythema on skin. Study participants showed higher preference for MN patches for long-acting contraception compared with conventional options, indicating strong interest and acceptability of MN patches in this study.

Recent Progress in Intelligent Wearable Sensors for Health Monitoring and Wound Healing Based on Biofluids

The intelligent wearable sensors promote the transformation of the health care from a traditional hospital-centered model to a personal portable device-centered model. There is an urgent need of real-time, multi-functional, and personalized monitoring of various biochemical target substances and signals based on the intelligent wearable sensors for health monitoring, especially wound healing. Under this background, this review article first reviews the outstanding progress in the development of intelligent, wearable sensors designed for continuous, real-time analysis, and monitoring of sweat, blood, interstitial fluid, tears, wound fluid, etc. Second, this paper reports the advanced status of intelligent wound monitoring sensors designed for wound diagnosis and treatment. The paper highlights some smart sensors to monitor target analytes in various wounds. Finally, this paper makes conservative recommendations regarding future development of intelligent wearable sensors.

Magneto-Responsive Microneedle Robots for Intestinal Macromolecule Delivery

Oral administration is the most convenient and commonly used approach for drug delivery, while it is still a challenge to overcome the complicated gastrointestinal barriers and realize efficient macromolecular drug absorption. Here, novel magneto-responsive microneedle robots are presented for efficient oral delivery of versatile macromolecules. These microneedle robots with three components of the magnetic substrate, the separable connection, and tips are generated by a Lego-brick-stacking-inspired multistage 3D fabrication strategy. With the assistance of commercial enteric capsule encapsulation, they can be taken orally and be released when entering the small intestine. Benefitting from their polarized magnetic substrate, the tips of the microneedle robots can orient to the small intestinal wall, overcome the barriers, insert into the tissue, and deliver encapsulated actives under specific magnetic fields. Besides, after the separable connection degrades, the tips can be left inside the tissue for continuous actives release, and the magnetic substrate can be excreted safely. Based on these features, the practical values of the microneedle robots are demonstrated by using them to orally deliver insulin and efficiently regulate the blood glucose of pigs. It is believed that the proposed microneedle robots can orally deliver diverse macromolecules and thus open a new chapter for oral administration.

Chinese herb microneedle patch for wound healing

Traditional Chinese medicine and Chinese herbs have a demonstrated value for disease therapy and sub-health improvement. Attempts in this area tend to develop new forms to make their applications more convenient and wider. Here, we propose a novel Chinese herb microneedle (CHMN) patch by integrating the herbal extracts, Premna microphylla and Centella asiatica, with microstructure of microneedle for wound healing. Such path is composed of sap extracted from the herbal leaves via traditional kneading method and solidified by plant ash derived from the brine induced process of tofu in a well-designed mold. Because the leaves of the Premna microphylla are rich in pectin and various amino acids, the CHMN could be imparted with medicinal efficacy of heat clearing, detoxicating, detumescence and hemostatic. Besides, with the excellent pharmaceutical activity of Asiatic acid extracted from Centella asiatica, the CHMN is potential in promoting relevant growth factor genes expression in fibroblasts and showing excellent performance in anti-oxidant, anti-inflammatory and anti-bacterial activity. Taking advantages of these pure herbal compositions, we have demonstrated that the derived CHMN was with dramatical achievement in anti-bacteria, inhibiting inflammatory, collagen deposition, angiogenesis and tissue reconstruction during the wound closure. These results indicate that the integration of traditional Chinese herbs with progressive technologies will facilitate the development and promotion of traditional Chinese medicine in modern society.

Smart Responsive Microarray Patches for Transdermal Drug Delivery and Biological Monitoring

Traditional drug delivery routes possess various disadvantages which make them unsuitable for certain population groups, or indeed unsuitable for drugs with certain physicochemical properties. As a result, a variety of alternative drug delivery routes have been explored in recent decades, including transdermal drug delivery. One of the most promising novel transdermal drug delivery technologies is a microarray patch (MAP), which can bypass the outermost skin barrier and deliver drugs directly into the viable epidermis and dermis. Unlike traditional MAPs which release loaded cargo simultaneously upon insertion into the skin, stimuli responsive MAPs based on biological stimuli are able to precisely release the drug in response to the need for additional doses. Thus, smart MAPs that are only responsive to certain external stimuli are highly desirable, as they provide safer and more efficient drug delivery. In addition to drug delivery, they can also be used for biological monitoring, which further expands their applications.

Keratinocyte membrane-mediated nanodelivery system with dissolving microneedles for targeted therapy of skin diseases

There is a lack of actively targeting drug delivery carriers for the topical treatment of epidermal diseases, which results in drug waste and an increased incidence of toxic side effects in the clinic. We recently discovered that epidermal cells (HaCaT cells) have homologous targeting functions and developed HaCaT cell membrane-coated pH-sensitive micelles for therapeutic active targeting of skin disease. We encapsulated shikonin in these biomimetic nanocarriers and found that the nanocarriers accumulated mainly in the active epidermis when delivered with karaya gum-fabricated water-soluble microneedles. The nanocarriers were internalized by the target cells, resulting in swelling of histidine fragments with protonation and subsequent triggering of drug release, which increased the therapeutic efficacy of shikonin against imiquimod-induced psoriatic epidermal hyperplasia. This emerging biomimetic delivery strategy is a new approach for improving the treatment of skin diseases and is also very promising for use in the field of cosmetics. Additionally, we found abnormally high protein expression of Na⁺/K⁺-ATPase in diseased skin; thus, this protein may be a biomarker of psoriasis.

Immediate detachment of microneedles by interfacial fracture for sustained delivery of a contraceptive hormone in the skin

Despite their high efficacy and safety, long-acting contraceptive methods are underutilized among women in some settings because they usually require injection or implantation by healthcare personnel. Here, we report a self-administrable microneedle (MN) patch for the rapid administration of a sustained-release contraceptive hormone delivery system into the skin that increases the simplicity and reliability of the MN delivery. We developed an immediate microneedle detachment system using a porous patch backing that has sufficient strength during MN insertion into skin under compression, but enables immediate detachment (< 1 s) of the MNs due to fracture at the MN - backing interface upon patch removal under tension from the skin surface. After patch application, the removed patch produced no biohazardous sharps waste, and was designed to achieve long-acting contraception by formulating poly(lactic-co-glycolic acid) MNs to slowly release the contraceptive hormone levonorgestrel for up to 1 month. Our combined strategy using immediate MN detachment in the skin and sustained drug delivery from the MNs could facilitate greater access to long-acting contraception by providing a simple and convenient option for self-administered, long-acting contraception.

Fabrication of pure-drug microneedles for delivery of montelukast sodium

Dissolving microneedle (MN) patches are usually formulated with a blend of drug and excipients added for mechanical strength and drug stabilization. In this study, we developed MNs made of pure drug to maximize drug loading capacity. MN patches were fabricated for transdermal delivery of montelukast sodium (MS) which is used to treat asthma and allergic rhinitis. We developed three different fabrication methods - solvent casting, melt casting, and solvent washing - and determined that filling molds with MS powder followed by a solvent washing method enabled MS to be loaded selectively to the MNs. Drug localization was confirmed with Raman imaging. MNs were able to penetrate in vitro and ex vivo skin models, and maintained strong mechanical properties during 6 months' storage at 22 °C. MS was also stable and compatible with the formulation used for the patch backing layer after 3 months' storage at 40 °C. MS delivery efficiency into skin was 55%, which enabled delivery of 3.2 mg MS into porcine skin ex vivo, which is in the range of MS doses in human clinical use. We conclude that the solvent washing method can be used to prepare MNs containing pure drug, such as MS at milligram doses in a ~ 1 cm² MN patch.

Lab under the Skin: Microneedle Based Wearable Devices

While the current smartwatches and cellphones can readily track mobility and vital signs, a new generation of wearable devices is rapidly developing to enable users to monitor their health parameters at the molecular level. Within this emerging class of wearables, microneedle-based transdermal sensors are in a prime position to play a key role in synergizing the significant advantages of dermal interstitial fluid (ISF) as a rich source of clinical indicators and painless skin pricking to allow the collection of real-time diagnostic information. While initial efforts of microneedle sensing focused on ISF extraction coupled with either on-chip analysis or off-chip instrumentation, the latest trend has been oriented toward assembling electrochemical biosensors on the tip of microneedles to allow direct continuous chemical measurements. In this context, significant advances have recently been made in exploiting microneedle-based devices for real-time monitoring of various metabolites, electrolytes, and therapeutics and toward the simultaneous multiplexed detection of key chemical markers; yet, there are several grand challenges that still exist. In this review, we outline current progress, recent trends, and new capabilities of microneedle-empowered sensors, along with the current unmet challenges and a future roadmap toward transforming the latest innovations in the field to commercial products.

Transdermal microneedles for the programmable burst release of multiple vaccine payloads

Repeated bolus injections are associated with higher costs and poor compliance and can hinder the implementation of global immunization campaigns. Here, we report the development and preclinical testing of patches of transdermal core-shell microneedles-which were fabricated by the micromoulding and alignment of vaccine cores and shells made from poly(lactic-co-glycolic acid) with varying degradability kinetics-for the preprogrammed burst release of vaccine payloads over a period of a few days to more than a month from a single administration. In rats, microneedles loaded with a clinically available vaccine (Prevnar-13) against the bacterium Streptococcus pneumoniae induced immune responses that were similar to immune responses observed after multiple subcutaneous bolus injections, and led to immune protection against a lethal bacterial dose. Microneedle patches delivering preprogrammed doses may offer an alternative strategy to prophylactic and therapeutic protocols that require multiple injections.

Nanomedicines and microneedles: a guide to their analysis and application

The fast-advancing progress in the research of nanomedicine and microneedle applications in the past two decades has suggested that the combination of the two concepts could help to overcome some of the challenges we are facing in healthcare. They include poor patient compliance with medication and the lack of appropriate administration forms that enable the optimal dose to reach the target site. Nanoparticles as drug vesicles can protect their cargo and deliver it to the target site, while evading the body's defence mechanisms. Unfortunately, despite intense research on nanomedicine in the past 20 years, we still haven't answered some crucial questions, e.g. about their colloidal stability in solution and their optimal formulation, which makes the translation of this exciting technology from the lab bench to a viable product difficult. Dissolvable microneedles could be an effective way to maintain and stabilise nano-sized formulations, whilst enhancing the ability of nanoparticles to penetrate the stratum corneum barrier. Both concepts have been individually investigated fairly well and many analytical techniques for tracking the fate of nanomaterials with their precious cargo, both in vitro and in vivo, have been established. Yet, to the best of our knowledge, a comprehensive overview of the analytical tools encompassing the concepts of microneedles and nanoparticles with specific and successful examples is missing. In this review, we have attempted to briefly analyse the challenges associated with nanomedicine itself, but crucially we provide an easy-to-navigate scheme of methods, suitable for characterisation and imaging the physico-chemical properties of the material matrix.

Microneedles for drug delivery: recent advances in materials and geometry for preclinical and clinical studies

INTRODUCTION

A microneedle array patch (MAP) has been studied as a means for delivering drugs or vaccines and has shown superior delivery efficiency compared to the conventional transdermal drug delivery system (TDD). This paper reviews recent advancements in the development of MAPs, with a focus on their size, shapes, and materials in preclinical and clinical studies for pharmaceutics.

AREA COVERED

We classified MAPs for drug delivery into four types: coated, dissolving, separable, and swellable. We covered their recent developments in materials and geometry in preclinical and clinical studies.

EXPERT OPINION

The design of MAPs needs to be determined based on what properties would be effective for the target diseases and purposes. In addition, in preclinical studies, it is necessary to consider not only the novelty of the formulations but also the feasibility of clinical application. Currently, clinical studies of microneedles loaded with various drugs and vaccines are in progress. When the regulation of pharmaceutical microneedles is established and more clinical studies are published, more drugs will be developed as microneedle products and clinical research will proceed. With these considerations, the microneedle array patch will be a better option for drug delivery.

Recent Advances in Engineered Materials for Immunotherapy-Involved Combination Cancer Therapy

Immunotherapy that can activate immunity or enhance the immunogenicity of tumors has emerged as one of the most effective methods for cancer therapy. Nevertheless, single-mode immunotherapy is still confronted with several critical challenges, such as the low immune response, the low tumor infiltration, and the complex immunosuppression tumor microenvironment. Recently, the combination of immunotherapy with other therapeutic modalities has emerged as a powerful strategy to augment the therapeutic outcome in fighting against cancer. In this review, recent research advances of the combination of immunotherapy with chemotherapy, phototherapy, radiotherapy, sonodynamic therapy, metabolic therapy, and microwave thermotherapy are summarized. Critical challenges and future research direction of immunotherapy-based cancer therapeutic strategy are also discussed.

A review of existing strategies for designing long-acting parenteral formulations: Focus on underlying mechanisms, and future perspectives

The need for long-term treatments of chronic diseases has motivated the widespread development of long-acting parenteral formulations (LAPFs) with the aim of improving drug pharmacokinetics and therapeutic efficacy. LAPFs have been proven to extend the half-life of therapeutics, as well as to improve patient adherence; consequently, this enhances the outcome of therapy positively. Over past decades, considerable progress has been made in designing effective LAPFs in both preclinical and clinical settings. Here we review the latest advances of LAPFs in preclinical and clinical stages, focusing on the strategies and underlying mechanisms for achieving long acting. Existing strategies are classified into manipulation of in vivo clearance and manipulation of drug release from delivery systems, respectively. And the current challenges and prospects of each strategy are discussed. In addition, we also briefly discuss the design principles of LAPFs and provide future perspectives of the rational design of more effective LAPFs for their further clinical translation.

Recent advances in microneedles-mediated transdermal delivery of protein and peptide drugs

Proteins and peptides have become a significant therapeutic modality for various diseases because of their high potency and specificity. However, the inherent properties of these drugs, such as large molecular weight, poor stability, and conformational flexibility, make them difficult to be formulated and delivered. Injection is the primary route for clinical administration of protein and peptide drugs, which usually leads to poor patient's compliance. As a portable, minimally invasive device, microneedles (MNs) can overcome the skin barrier and generate reversible microchannels for effective macromolecule permeation. In this review, we highlighted the recent advances in MNs-mediated transdermal delivery of protein and peptide drugs. Emphasis was given to the latest development in representative MNs design and fabrication. We also summarize the current application status of MNs-mediated transdermal protein and peptide delivery, especially in the field of infectious disease, diabetes, cancer, and other disease therapy. Finally, the current status of clinical translation and a perspective on future development are also provided.

Human-centred design of a new microneedle-based hormonal contraceptive delivery system

Background: It is estimated that 225 million women worldwide have an unmet need for family planning, and more than half live in low- and middle-income countries. Increasing the choice of contraceptive methods available can reduce this unmet need. Microneedle drug delivery systems represent a new technology for minimally invasive self-administration of contraceptives. We explored stakeholders’ views on different aspects of a proposed microneedle-based hormonal contraceptive delivery system. The feedback was used to iteratively develop this delivery system. Methods: Focus group discussions and semi-structured interviews were conducted with potential stakeholders (women and trans males of childbearing age, their partners, and health professionals and organisations that provide family planning advice and contraception services) in Uganda, The Gambia, Malawi, and the UK, exploring concept acceptability and gathering feedback on different aspects of design and usability of the proposed delivery system. Results: Participants viewed the concept of a new, microneedle-based contraceptive favourably. In Uganda, participants were presented with 7 different prototype applicators and identified desirable features of a preferred delivery device; their input reducing the number of prototypes that were subsequently evaluated by stakeholders in The Gambia and the UK. Participants in these countries helped to identify and/or confirm the most desirable characteristics of the applicator, resulting in design consolidation into a refined concept applicator. The final, optimised applicator prototype was validated during user research in Malawi. This human-centred design approach was also used to iteratively develop an information leaflet for the device. During these user studies, other preferred aspects of a contraceptive delivery system were also evaluated, such as anatomical site of application, duration of action, and return to fertility. Conclusions: A new microneedle-based contraceptive delivery system was iteratively developed using a human-centred design approach and was favourably received by potential stakeholders. The product is now being refined for testing in pre-clinical studies.

Translation of Polymeric Microneedles for Treatment of Human Diseases: Recent Trends, Progress, and Challenges

The ongoing search for biodegradable and biocompatible microneedles (MNs) that are strong enough to penetrate skin barriers, easy to prepare, and can be translated for clinical use continues. As such, this review paper is focused upon discussing the key points (e.g., choice polymeric MNs) for the translation of MNs from laboratory to clinical practice. The review reveals that polymers are most appropriately used for dissolvable and swellable MNs due to their wide range of tunable properties and that natural polymers are an ideal material choice as they structurally mimic native cellular environments. It has also been concluded that natural and synthetic polymer combinations are useful as polymers usually lack mechanical strength, stability, or other desired properties for the fabrication and insertion of MNs. This review evaluates fabrication methods and materials choice, disease and health conditions, clinical challenges, and the future of MNs in public healthcare services, focusing on literature from the last decade.

Novel tip-loaded dissolving and implantable microneedle array patches for sustained release of finasteride

Finasteride (FND) is a competitive inhibitor of 5α-reductase, an enzyme involved in benign prostatic hyperplasia (BPH) and androgenic alopecia. FND is administered in oral, often lifelong treatments, increasing the pill burden of polymedicated patients. Microneedle array patches (MAPs) are minimally invasive devices that painlessly pierce the outermost layers of the skin, forming slowly-dissolving drug depots in the dermis, which can release drugs over weeks or months, making this platform an attractive, patient-friendly option for long-term treatments. This work describes the development of long-acting dissolving and implantable PLGA MAPs aimed for systemic release of FND for at least two weeks. Mechanically strong tip-loaded MAPs with pyramidal geometry were obtained using micromoulding methodology. In vitro studies revealed that the dissolving and implantable MAPs were able to release the drug for over 7 and 14 days, respectively. Skin deposition experiments in Franz cells demonstrated that after 24 h, dissolving and implantable MAPs were able to deposit 629.00 ± 214.54 μg and 1861.64 ± 383.30 μg of FND in the skin, respectively. On the other hand, transdermal permeation studies showed that both formulations produced a slow release of the drug to the receptor compartment of the Franz cells, with dissolving and implantable MAPs releasing 90.43 ± 6.20 μg and 27.80 ± 3.94 μg of FND after 24 h. The formulations described here could be an alternative to current oral treatments, having the potential to deliver the drug for extended periods, simplifying the treatment of BPH and androgenic alopecia.

Polymeric microneedle‐mediated sustained release systems: Design strategies and promising applications for drug delivery

Parenteral sustained release drug formulations, acting as preferable platforms for long-term exposure therapy, have been wildly used in clinical practice. However, most of these delivery systems must be given by hypodermic injection. Therefore, issues including needle-phobic, needle-stick injuries and inappropriate reuse of needles would hamper the further applications of these delivery platforms. Microneedles (MNs) as a potential alternative system for hypodermic needles can benefit from minimally invasive and self-administration. Recently, polymeric microneedle-mediated sustained release systems (MN@SRS) have opened up a new way for treatment of many diseases. Here, we reviewed the recent researches in MN@SRS for transdermal delivery, and summed up its typical design strategies and applications in various diseases therapy, particularly focusing on the applications in contraception, infection, cancer, diabetes, and subcutaneous disease. An overview of the present clinical translation difficulties and future outlook of MN@SRS was also provided.

Human-centred design of a new microneedle-based hormonal contraceptive delivery system

Background: It is estimated that 225 million women worldwide have an unmet need for family planning, and more than half live in low- and middle-income countries. Increasing the choice of contraceptive methods available can reduce this unmet need. Microneedle drug delivery systems represent a new technology for minimally invasive self-administration of contraceptives. We explored stakeholders’ views on different aspects of a proposed microneedle-based hormonal contraceptive delivery system. The feedback was used to iteratively develop this delivery system. Methods: Focus group discussions and semi-structured interviews were conducted with potential stakeholders (women and trans males of childbearing age, their partners, and health professionals and organisations that provide family planning advice and contraception services) in Uganda, The Gambia, Malawi, and the UK, exploring concept acceptability and gathering feedback on different aspects of design and usability of the proposed delivery system. Results: Participants viewed the concept of a new, microneedle-based contraceptive favourably. In Uganda, participants were presented with 7 different prototype applicators and identified desirable features of a preferred delivery device; their input reducing the number of prototypes that were subsequently evaluated by stakeholders in The Gambia and the UK. Participants in these countries helped to identify and/or confirm the most desirable characteristics of the applicator, resulting in design consolidation into a refined concept applicator. The final, optimised applicator prototype was validated during user research in Malawi. This human-centred design approach was also used to iteratively develop an information leaflet for the device. During these user studies, other preferred aspects of a contraceptive delivery system were also evaluated, such as anatomical site of application, duration of action, and return to fertility. Conclusions: A new microneedle-based contraceptive delivery system was iteratively developed using a human-centred design approach and was favourably received by potential stakeholders. The product is now being refined for testing in pre-clinical studies.

Microarray patches: Breaking down the barriers to contraceptive care and HIV prevention for women across the globe

Despite the existence of a variety of contraceptive products for women, as well as decades of research into the prevention and treatment of human immunodeficiency virus (HIV), there is still a globally unmet need for easily accessible, acceptable, and affordable products to protect women's sexual and reproductive health. Microarray patches (MAPs) are a novel platform being developed for the delivery of hormonal contraception and antiretroviral drugs. MAPs provide enhanced drug delivery to the systemic circulation via the transdermal route when compared to transdermal patches, oral and injectable formulations. These minimally invasive patches can be self-administered by the user, reducing the burden on health care personnel. Since MAPs represent needle-free drug delivery, no sharps waste is generated after application, thereby eliminating possible MAP reuse and risk of needle-stick injuries. This review discusses the administration of contraceptive and antiretroviral drugs using MAPs, their acceptability by end-users, and the future perspective of the field.

Build an implanted "arsenal": detachable microneedles for NIR-triggered cancer photothermo-chemotherapy

The current trend in tumor research is shifting from monotherapy to multimodal therapy. However, how to achieve on-demand drug delivery and minimize the invasiveness of treatment are still big challenges. Herein, we present a detachable microneedles (MNs) system, which consists of polycaprolactone (PCL) needles and polyvinylpyrrolidone/poly (vinyl alcohol) substrate, to build an implanted drug depot for on-demand photothermo-chemotherapy. Owing to the dissolvability of the substrate, detachable MNs can intradermally implant PCL needles loaded with photothermal conversion agent Prussian blue nanocubes (PB NCs) and chemotherapeutics doxorubicin hydrochloride (Dox·HCl). Once near-infrared light irradiates, PB NCs could translate light to local regional hyperthermia, which not only ablates cancer cells but also meltPCL to accelerate the diffusion of Dox·HCl. These MNs displayed a stable and repeatable photothermal effect under NIR irradiation. The ex vivo experiments using isolated swine skin demonstrated the as needed Dox·HCl delivery triggered by NIR light. Moreover, the robust antitumor efficacy of the MN system was proved in KB tumor-bearing nude mice under three timed NIR irradiation. Therefore, the developed detachable MNs which could build implanted "arsenal" for on-demand photothermo-chemotherapy have a bright future in tumor suppression.

Fabrication of Rapidly Separable Microneedles for Transdermal Delivery of Metformin on Diabetic Rats

In this work, the rapidly separable microneedles (MNs) consisted of needle-tips and supporting bases have been fabricated by a step-by-step coating method. Poly (vinyl alcohol) (PVA) have been used to prepare the needle-tips of MNs in which they are capped on the solvable supporting bases consisted of sodium bicarbonate, poly (vinyl pyrolidone) (PVP), and tartaric acid (TA) (NaHCO₃/PVP/TA). After insertion into the skin, the needle-tips can be separated rapidly from the patches within 90 s due to the generation of air bubbles in the supporting bases by the reaction between NaHCO₃ and TA after absorption of tissue fluid, leading to the needle-tips remaining in the skin tissue. Metformin, a hypoglycemic drug, encapsulated in the needle-tips of MNs can be released due to swelling and decomposition of PVA by the absorption of tissue fluid. To investigate the pharmacological effect via transdermal delivery route, metformin-loaded MNs are applied on the diabetic SD rats induced by streptozotocin (STZ). They exhibit a longer hypoglycemic effect in vivo than that of subcutaneous injection. These results indicated the as-fabricated rapidly separable MNs present a promising platform for transdermal delivery of drugs against diabetic patients.

Ultrasound-responsive polymer-based drug delivery systems

Ultrasound-responsive polymeric materials have received a tremendous amount of attention from scientists for several decades. Compared to other stimuli-responsive materials (such as UV-, thermal-, and pH-responsive materials), these smart materials are more applicable since they allow more efficient drug delivery and targeted treatment by fairly non-invasive means. This review describes the recent advances of such ultrasound-responsive polymer-based drug delivery systems and illustrates various applications. More specifically, the mechanism of ultrasound-induced drug delivery, typical formulations, and biomedical applications (tumor therapy, disruption of blood-brain barrier, fighting infectious diseases, transdermal drug delivery, and enhanced thrombolysis) are summarized. Finally, a perspective on the future research directions for the development of ultrasound-responsive polymeric materials to facilitate a clinical translation is given.

Optimizing the design of a contraceptive microarray patch: a discrete choice experiment on women's preferences in India and Nigeria

Background

Efforts are underway to develop an easy-to-use contraceptive microarray patch (MAP) that could expand the range of self-administrable methods. This paper presents results from a discrete choice experiment (DCE) designed to support optimal product design.

Methods

We conducted a DCE survey of users and non-users of contraception in New Delhi, India (496 women) and Ibadan, Nigeria (two versions with 530 and 416 women, respectively) to assess stated preferences for up to six potential product attributes: effect on menstruation, duration of effectiveness, application pain, location, rash after application, and patch size. We estimated Hierarchical Bayes coefficients (utilities) for each attribute level and ran simulations comparing women’s preferences for hypothetical MAPs with varying attribute combinations.

Results

The most important attributes of the MAP were potential for menstrual side effects (55% of preferences in India and 42% in Nigeria) and duration (13% of preferences in India and 24% in Nigeria). Women preferred a regular period over an irregular or no period, and a six-month duration to three or one month. Simulations show that the most ideal design would be a small patch, providing 6 months of protection, that would involve no pain on administration, result in a one-day rash, and be applied to the foot.

Conclusions

To the extent possible, MAP developers should consider method designs and formulations that limit menstrual side effects and provide more than one month of protection.