Topical Inserts: A Versatile Delivery Form for HIV Prevention

Vaginally-delivered fast-dissolving antibody tablets (FDAT) for on-demand non-hormonal contraception and multi-purpose protection

There are limited options available for safe and effective non-hormonal contraceptives or methods that block sexually transmitted diseases such as herpes simplex virus (HSV). Direct vaginal delivery of monoclonal antibodies (mAb) represents a promising approach toward both goals, but clinical translation has been limited by the lack of convenient dosage forms that can quickly and stably deliver mAbs without mess. Here, we report the development of fast-dissolving antibody tablets (FDAT) that allow for the complete release of fully functional mAbs within seconds in vaginal fluid simulants, and within two minutes in fresh human cervicovaginal mucus ex vivo. As proof-of-concept, we developed two FDAT formulations: one for HSV8, a potent neutralizing mAb against both HSV Type 1 and 2, and a second for MM008, a unique 10-Fab anti-sperm mAb that induces sperm agglutination and inhibits progressive sperm motility with picomolar potency. In sheep studies, vaginally inserted HSV8-FDAT achieved uniform distribution in different parts of the vagina within minutes, while fully maintaining HSV8 neutralization activity. Similarly, MM008-FDAT completely eliminated all progressively motile sperm within 2 min of human semen instillation. Finally, the FDATs were stable for at least 3 months of storage at room temperature within desiccated water-impermeant foil pouches, and repeated daily application of FDATs for 7 days was safe and well tolerated in sheep. These results underscore the potentials of the FDAT platform for delivery of biologic interventions to reinforce female reproductive health.

Bigels based on polyelectrolyte complexes as vaginal drug delivery systems

Bigels in which the cationic polymer -chitosan- is combined with an anionic polymer -karaya gum, pectin or xanthan gum- were prepared. These polymers, thanks to the attraction of their charged surface groups, are liable to form a polyelectrolyte complex that would modify the characteristics of the bigel. The obtained bigels were subsequently freeze-dried and tested to study their behavior against different conditions occurring in the vaginal environment. Swelling and drug release profiles have been evaluated in a medium that simulates the ordinary vaginal conditions and simulating the conditions after ejaculation. Thanks to the formation of polyelectrolyte complexes, the bigel is able to provide a pH-independent sustained drug release. However, when one of the polymers predominates, the release of the active ingredient turns out to be pH-dependent -which can also be beneficial in some therapeutic applications-. It has been proved that the inclusion of a higher percentage of chitosan in the bigel improves its mechanical properties, while the mucoadhesivity of the system can be improved by increasing the anionic polymer. The versatility of these systems in modulating their physicochemical properties, provides a substantial advantage over the formulations currently available on the market for vaginal drug delivery.

Formulation development of dual-compartment topical inserts combining tenofovir alafenamide and elvitegravir for flexible on-demand HIV prevention

Pre-exposure prophylaxis (PrEP) has emerged as a prominent approach for the prevention of HIV infections. While the latest advances have resulted in effective oral and injectable product options, there are still gaps in on-demand, event-driven, topical products for HIV prevention that are safe and effective. Here we describe the formulation development of a dual-compartment topical insert containing tenofovir alafenamide fumarate (TAF) and elvitegravir (EVG) that may be administered when needed, vaginally or rectally, pre- or post-coitus, for flexible HIV prophylaxis. Specifically, we describe the lab-scale formulation development, preclinical mucosal safety and pharmacokinetics (PK) testing in rabbits, long-term stability, and scale-up clinical manufacturing of the lead TAF/EVG (20 mg/16 mg) inserts, which are currently in clinical stages of development. As designed, the inserts are small, discreet and portable, offering a number of promising attributes, such as simple and robust direct-compression manufacturing, fast initial disintegration/dissolution, and suitable mechanical strengths showing low hardness (<8 kg), friability (<1 %), and moisture content (<1 %). The inserts initiated disintegration quickly (∼ ≤ 15 min) providing full in vitro release (>90 %) of TAF and EVG within 60 min of dissolution. The lead insert was selected from formulation prototypes that met the evaluation criteria for manufacturability and characterization, along with a dose-ranging PK study in non-human primates. Successful technology transfer for clinical development of the lead TAF/EVG (20 mg/16 mg) insert was confirmed under current Good Manufacturing Practices (cGMP) conditions. Based on the 12 months (lab-scale) and 24 months (clinical batch) stability data, the TAF/EVG inserts are projected to have a long shelf life of over 2 years, if stored at or below 30 °C/65 % RH. Overall, these newly designed topical inserts have formulation properties that enable stable storage and fast release of the antiretroviral payload from a small, portable and discreet dosage form. They are safe and effective when applied vaginally or rectally, before or after coitus, providing the basis for a new method of flexible on-demand HIV prevention for cisgender and transgender women and men. The TAF/EVG inserts are currently the most clinically advanced on-demand topical product, as attested by their completed and ongoing clinical trials.

A Phase 1 Clinical Trial to Assess the Safety and Pharmacokinetics of a Tenofovir Alafenamide/Elvitegravir Insert Administered Rectally for HIV Prevention

BACKGROUND

On-demand topical products could be an important tool for human immunodeficiency virus (HIV) prevention. We evaluated the safety, pharmacokinetics, and ex vivo pharmacodynamics of a tenofovir alafenamide/elvitegravir (TAF/EVG, 20 mg/16 mg) insert administered rectally.

METHODS

MTN-039 was a phase 1, open-label, single-arm, 2-dose study. Blood, rectal fluid, and rectal tissue were collected over 72 hours following rectal administration of 1 and 2 TAF/EVG inserts for each participant.

RESULTS

TAF/EVG inserts were safe and well tolerated. EVG and tenofovir (TFV) were detected in blood plasma at low concentrations: median peak concentrations after 2 inserts were EVG 2.4 ng/mL and TFV 4.4 ng/mL. Rectal tissue EVG peaked at 2 hours (median, 2 inserts = 9 ng/mg) but declined to below limit of quantification in the majority of samples at 24 hours, whereas tenofovir diphosphate (TFV-DP) remained high >2000 fmol/million cells for 72 hours with 2 inserts. Compared to baseline, median cumulative log10 HIV p24 antigen of ex vivo rectal tissue HIV infection was reduced at each time point for both 1 and 2 inserts (P < .065 and P < .039, respectively).

DISCUSSION

Rectal administration of TAF/EVG inserts achieved high rectal tissue concentrations of EVG and TFV-DP with low systemic drug exposure and demonstrable ex vivo inhibition of HIV infection for 72 hours. Clinical Trials Registration . NCT04047420.

History of Rectal Product Use and Country of Residence Influence Preference for Rectal Microbicide Dosage Forms Among Young Sexual and Gender Minorities: A Multi-country Trial Comparing Placebo Douche, Suppository, and Insert Products

The DESIRE Study (MTN-035) explored product preference among three placebo rectal microbicide (RM) formulations, a rectal douche (RD), a suppository, and an insert, among 210 sexually active transgender people and men who have sex with men in five counties: the United States, Peru, Thailand, South Africa, and Malawi. Participants used each product prior to receptive anal sex (RAS) for 1 month, following a randomly assigned sequence, then selected their preferred product via computer assisted self-interview. In-depth interviews examined reasons for preference. We compared product preference and prior product use by country to explore whether geographic location and experience with the similar products impacted preference. A majority in the United States (56%) and Peru (58%) and nearly half in South Africa (48%) preferred the douche. Most in Malawi (59%) preferred the suppository, while half in Thailand (50%) and nearly half in South Africa (47%) preferred the insert. Participants who preferred the douche described it as quick and easy, already routinized, and serving a dual purpose of cleansing and protecting. Those who preferred the insert found it small, portable, discreet, with quick dissolution. Those who preferred the suppository found the size and shape acceptable and liked the added lubrication it provided. Experience with product use varied by country. Participants with RD experience were significantly more likely to prefer the douche (p = 0.03). Diversifying availability of multiple RM dosage forms can increase uptake and improve HIV prevention efforts globally.

Extended Postexposure Protection Against Vaginal Simian/Human Immunodeficiency Virus Infection With Tenofovir Alafenamide Fumarate/Elvitegravir Inserts in Macaques

Vaginal inserts that can be used on demand before or after sex may be a desirable human immunodeficiency virus (HIV) prevention option for women. We recently showed that inserts containing tenofovir alafenamide fumarate (TAF, 20 mg) and elvitegravir (EVG, 16 mg) were highly protective against repeated simian/human immunodeficiency virus (SHIV) vaginal exposures when administered to macaques 4 hours before or after virus exposure (93% and 100%, respectively). Here, we show in the same macaque model that insert application 8 hours or 24 hours after exposure maintains high efficacy (94.4% and 77.2%, respectively). These data extend the protective window by TAF/EVG inserts and inform their clinical development for on-demand prophylaxis in women.

A conjoint experiment of three placebo rectal products used with receptive anal sex: results from MTN-035

INTRODUCTION

End-user perspectives are vital to the design of new biomedical HIV prevention products. Conjoint analysis can support the integration of end-user perspectives by examining their preferences of potential pre-exposure prophylaxis (PrEP) products. The Microbicides Trial Network (MTN) 035 protocol examined three placebo rectal dosage forms (insert, enema and suppository) that could deliver PrEP prior to receptive anal sex (RAS).

METHODS

Between April 2019 and July 2020, we enrolled 217 HIV-negative, cisgender men who have sex with men (MSM; n = 172; 79.3%) and transgender people (n = 47; 20.7%) ages 18-35 into a randomized cross-over trial across Malawi, Peru, South Africa, Thailand and the United States. Participants used each product prior to RAS over 4-week periods. Participants completed a conjoint experiment where they selected between random profiles using seven features (dosage form, timing of use before sex, side effects, duration of protection, effectiveness, frequency of use and need for a prescription).

RESULTS

Effectiveness was the strongest determinant of choice (30.4%), followed by modality (18.0%), potential side effects (17.2%), frequency of use (10.8%), duration of protection (10.4%), timing of use before sex (7.4%) and need for a prescription (5.9%). Relative utility scores indicated that the most desirable combination of attributes was a product with 95% efficacy, used 30 minutes before sex, offering a 3- to 5-day protection window, used weekly, having no side effects, in the form of an enema and available over-the-counter.

CONCLUSIONS

Choice in next-generation PrEP products is highly desired by MSM and transgender people, as no one-size-fits-all approach satisfies all the preferences. MTN-035 participants weighed product features differently, recognizing the need for diverse, behaviourally congruent biomedical options that fit the needs of intended end-users.

Development of Dispersible Vaginal Tablets of Tenofovir Loaded Mucoadhesive Chitosan Microparticles for Anti-HIV Pre-Exposure Prophylaxis

Tenofovir disoproxil fumarate (TDF)-loaded bioadhesive chitosan microparticles (CM) were developed by an emulsification internal gelation technique. Among different batches produced, ECH-4 was found to display a high % entrapment efficiency (68.93 ± 1.76%) and sustained drug release of 88.05 ± 0.38% at 24 h. Solid state characterization of ECH-4 employing DSC and PXRD indicated that the TDF existed in an amorphous state as a solid-solid solution in chitosan. Scanning electron microscopy revealed CM of ECH-4 was spherical in shape with a rough surface topography. Laser scattering analysis using Malvern Master sizer indicated that particle size of ECH-4 was in the range of 0.52 ± 0.10 μm to 284.79 ± 21.42 μm with a surface-mean diameter of 12.41 ± 0.06 μm. Ex vivo mucoadhesion studies using rabbit mucosa as a substrate indicated that 10.34 ± 2.08% of CM of ECH-4 was retained at the end of 24 h. The microparticles of ECH-4 were incorporated into dispersible tablets (DT-TCM) intended for intravaginal administration, in view to arrest the pre-exposure transmission of HIV during sexual intercourse. In vitro release from the dispersible tablet (F3) into simulated vaginal fluid (pH 4.5) displayed a sustained release profile of TDF as 89.98 ± 1.61% of TDF was released at 24 h. The in vitro dissolution profile of the DT-TCM was found to be similar to that of TDF loaded CM with the values of f1 (difference factor) and f2 (similarity factor) being 1.52 and 78.02, respectively. Therefore, DT-TCM would be a promising novel drug delivery platform for pre-exposure prophylaxis against HIV.

Strategic actions to advance multipurpose prevention technologies in low- and middle-income countries

Background

HIV, other sexually transmitted infections (STIs) and unintended pregnancies are critical and interlinked health risks for millions of women of reproductive age worldwide. Multipurpose prevention technologies (MPTs) offer an innovative approach for expanding combined pregnancy and/or disease prevention. So far, MPT development efforts have focused mostly on HIV prevention, but about half of product candidates comprise compounds active against non-HIV STIs as well. This review aims to provide a framework that promotes the efficient advancement of the most promising preclinical products through the development pathway and into the hands of end-users, with a focus on women in low- and middle-income countries (L/MICs).

Methods

This mini review provides a summary of the current landscape of the MPT field. It comprises a landscape assessment of MPTs in development, complemented by a series of 28 in-depth, semi-structured key informant interviews (KIIs) with experts representing different L/MIC perspectives.

Main results

We identified six primary action strategies to advance MPTs for L/MICs, including identification of key research gaps and priorities. For each action strategy, progress to date and key recommendations are included.

Conclusions

To realize the life-saving potential of MPTs and maximize the momentum made to date, a strategic, collaborative and well-funded response to the gaps and next steps outlined in this paper is critical. A coordinated response can add rigor and efficiency to the development process, to successfully advance the most promising MPT products to the hands of end-users.

A phase I study to assess safety, pharmacokinetics, and pharmacodynamics of a vaginal insert containing tenofovir alafenamide and elvitegravir

Background

New multi-purpose prevention technology (MPT) products are needed to prevent human immunodeficiency virus (HIV) and herpes simplex virus type 2 (HSV2). In this study, we evaluated a fast-dissolve insert that may be used vaginally or rectally for prevention of infection.

Objective

To describe the safety, acceptability, multi-compartment pharmacokinetics (PK), and in vitro modeled pharmacodynamics (PD) after a single vaginal dose of an insert containing tenofovir alafenamide (TAF) and elvitegravir (EVG) in healthy women.

Methods

This was a Phase I, open-label, study. Women (n=16) applied one TAF (20mg)/EVG (16mg) vaginal insert and were randomized (1:1) to sample collection time groups for up to 7 days post dosing. Safety was assessed by treatment-emergent adverse events (TEAEs). EVG, TAF and tenofovir (TFV) concentrations were measured in plasma, vaginal fluid and tissue, and TFV-diphosphate (TFV-DP) concentration in vaginal tissue. PD was modeled in vitro by quantifying the change in inhibitory activity of vaginal fluid and vaginal tissue against HIV and HSV2 from baseline to after treatment. Acceptability data was collected by a quantitative survey at baseline and post treatment.

Results

The TAF/EVG insert was safe, with all TEAEs graded as mild, and acceptable to participants. Systemic plasma exposure was low, consistent with topical delivery, while high mucosal levels were detected, with median TFV vaginal fluid concentrations exceeding 200,000 ng/mL and 1,000 ng/mL for up to 24 hours and 7 days post dosing, respectively. All participants had vaginal tissue EVG concentrations of > 1 ng/mg at 4 and 24 hours post dosing. The majority had tissue TFV-DP concentrations exceeding 1000 fmol/mg by 24 - 72 hours post dosing. Vaginal fluid inhibition of HIV-1 and HSV-2 in vitro significantly increased from baseline and was similarly high at 4 and 24 hours post dosing. Consistent with high tissue TFV-DP concentrations, p24 HIV antigen production from ectocervical tissues infected ex vivo with HIV-1 significantly decreased from baseline at 4 hours post dosing. HSV-2 production from tissue also decreased post treatment.

Conclusions

A single dose of TAF/EVG inserts met PK benchmarks, with PK data supporting an extended window of high mucosal protection. PD modeling supports mucosal protection against both HIV-1 and HSV-2. The inserts were safe and highly acceptable.

Clinical trial registration

ClinicalTrials.gov, identifier NCT03762772.

Women for science and science for women: Gaps, challenges and opportunities towards optimizing pre-exposure prophylaxis for HIV-1 prevention

Preventing new HIV infections remains a global challenge. Young women continue to bear a disproportionate burden of infection. Oral pre-exposure prophylaxis (PrEP), offers a novel women-initiated prevention technology and PrEP trials completed to date underscore the importance of their inclusion early in trials evaluating new HIV PrEP technologies. Data from completed topical and systemic PrEP trials highlight the role of gender specific physiological and social factors that impact PrEP uptake, adherence and efficacy. Here we review the past and current developments of HIV-1 prevention options for women with special focus on PrEP considering the diverse factors that can impact PrEP efficacy. Furthermore, we highlight the importance of inclusion of female scientists, clinicians, and community advocates in scientific efforts to further improve HIV prevention strategies.

Single dose topical inserts containing tenofovir alafenamide fumarate and elvitegravir provide pre- and post-exposure protection against vaginal SHIV infection in macaques

BACKGROUND

Vaginal products for HIV prevention that can be used on-demand before or after sex may be a preferable option for women with low frequency or unplanned sexual activity or who prefer not to use daily or long-acting pre-exposure prophylaxis (PrEP). We performed dose ranging pharmacokinetics (PK) and efficacy studies of a vaginally applied insert containing tenofovir alafenamide fumarate (TAF) and elvitegravir (EVG) in macaques under PrEP or post-exposure prophylaxis (PEP) modalities.

METHODS

PK studies were performed in 3 groups of pigtailed macaques receiving inserts with different fixed-dose combinations of TAF and EVG (10/8, 20/16 and 40/24 mg). PrEP and PEP efficacy of a selected insert was investigated in a repeat exposure vaginal SHIV transmission model. Inserts were administered 4 h before (n = 6) or after (n = 6) repeated weekly SHIV exposures. Infection outcome was compared with macaques receiving placebo inserts (n = 12).

FINDINGS

Dose ranging studies showed rapid and sustained high drug concentrations in vaginal fluids and tissues across insert formulations with minimal dose proportionality. TAF/EVG (20/16 mg) inserts were selected for efficacy evaluation. Five of the 6 animals receiving these inserts 4 h before and 6/6 animals receiving inserts 4 h after SHIV exposure were protected after 13 challenges (p = 0.0088 and 0.0077 compared to placebo, respectively). The calculated PrEP and PEP efficacy was 91.0% (95% CI = 32.2%-98.8%) and 100% (95% CI = undefined), respectively.

INTERPRETATION

Inserts containing TAF/EVG provided high protection against vaginal SHIV infection when administered within a 4 h window before or after SHIV exposure. Our results support the clinical development of TAF/EVG inserts for on-demand PrEP and PEP in women.

FUNDING

Funded by CDC intramural funds, an interagency agreement between CDC and USAID (USAID/CDC IAA AID-GH-T-15-00002), and by the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) through the U.S. Agency for International Development (USAID) under a Cooperative Agreement (AID-OAA-A-14-00010) with CONRAD/Eastern Virginia Medical School.

Application of Sol–Gels for Treatment of Gynaecological Conditions—Physiological Perspectives and Emerging Concepts in Intravaginal Drug Delivery

Approaches for effective and sustained drug delivery to the female reproductive tract (FRT) for treating a range of gynaecological conditions remain limited. The development of versatile delivery platforms, such as soluble gels (sol–gels) coupled with applicators/devices, holds considerable therapeutic potential for gynaecological conditions. Sol–gel systems, which undergo solution-to-gel transition, triggered by physiological conditions such as changes in temperature, pH, or ion composition, offer advantages of both solution- and gel-based drug formulations. Furthermore, they have potential to be used as a suitable drug delivery vehicle for other novel drug formulations, including micro- and nano-particulate systems, enabling the delivery of drug molecules of diverse physicochemical character. We provide an anatomical and physiological perspective of the significant challenges and opportunities in attaining optimal drug delivery to the upper and lower FRT. Discussion then focuses on attributes of sol–gels that can vastly improve the treatment of gynaecological conditions. The review concludes by showcasing recent advances in vaginal formulation design, and proposes novel formulation strategies enabling the infusion of a wide range of therapeutics into sol–gels, paving the way for patient-friendly treatment regimens for acute and chronic FRT-related conditions such as bacterial/viral infection control (e.g., STDs), contraception, hormone replacement therapy (HRT), infertility, and cancer.

Systemic delivery of tenofovir alafenamide using dissolving and implantable microneedle patches

The human immunodeficiency virus (HIV) remains a global health concern, with 37.7 million people currently living with the infection and 1.5 million new cases every year. Current antiretroviral (ARV) therapies are administered through the oral route daily, often in lifelong treatments, leading to pill fatigue and poor treatment adherence. Therefore, the development of novel formulations for the administration ARV drugs using alternative routes is actively sought out. In this sense, microneedle array patches (MAPs) offer a unique user-centric platform that can be painlessly self-applied to the skin and deliver drugs to the systemic circulation. In this work, dissolving and implantable MAPs loaded with the tenofovir alafenamide (TAF) were developed with the aim of releasing the drug systemically. Both MAPs were sufficiently strong to pierce excised neonatal full-thickness porcine skin and form drug depots. In vitro release experiments performed in dialysis membrane models, demonstrated a relatively fast delivery of the drug in all cases. Franz cells experiments revealed that dissolving and implantable MAPs deposited 47.87 ​± ​16.33 ​μg and 1208.04 ​± ​417.9 ​μg of TAF in the skin after 24 ​h. Pharmacokinetic experiments in rats demonstrated a fast metabolization of TAF into tenofovir, with a rapid elimination of the metabolite from the plasma. The MAPs described in this work could be used as an alternative to current oral treatments for HIV management.

Pharmacokinetics of vaginally applied integrase inhibitors in macaques

OBJECTIVES

We conducted a detailed pharmacokinetic assessment in macaques treated with vaginal gels formulated with HIV integrase strand transfer inhibitors (INSTIs) to better understand drug distribution and identify INSTI concentrations associated with previously demonstrated in vivo protection against vaginal simian HIV challenge.

METHODS

Six macaques received vaginal gel containing 1% raltegravir (30 mg) once-weekly over 6 weeks. Following a washout period, five macaques received once-weekly gel containing 0.23% L-870,812 (7 mg). Drug concentrations were measured in plasma, mucosal fluids and vaginal tissues at baseline and 2, 5 and 24 h post-dosing.

RESULTS

The median maximum concentration (Cmax) for raltegravir and L-870,812 in plasma was below the limit of quantification and 41.1 ng/mL, respectively. The Cmax in vaginal fluids (1441 and 1250 μg/mL) and tissues (266.7 and 368.4 μg/g) was achieved 2-5 h after dosing, respectively. A similar half-life was observed for raltegravir and L-870,812 in vaginal fluids (8-10 h) and remained 3-4 orders of magnitude above the protein-adjusted IC95 (0.016 and 0.106 μg/mL, respectively) at 24 h. Drug concentrations in vaginal fluids correlated well with those in vaginal tissues (Pearson r ≥ 0.788). Both drugs were consistently detected in rectal fluids 2 h after vaginal dosing, albeit at much lower levels (31-92-fold) than those in vaginal fluids.

CONCLUSIONS

To the best of our knowledge, this study provides the first data on INSTI levels in vaginal tissues associated with in vivo protection and demonstrates rectal drug distribution of INSTIs after vaginal dosing. These findings may inform dose selection for topical products with INSTIs for HIV prevention.

Women-specific routes of administration for drugs: A critical overview

The woman's body presents a number of unique anatomical features that can constitute valuable routes for the administration of drugs, either for local or systemic action. These are associated with genitalia (vaginal, endocervical, intrauterine, intrafallopian and intraovarian routes), changes occurring during pregnancy (extra-amniotic, intra-amniotic and intraplacental routes) and the female breast (breast intraductal route). While the vaginal administration of drug products is common, other routes have limited clinical application and are fairly unknown even for scientists involved in drug delivery science. Understanding the possibilities and limitations of women-specific routes is of key importance for the development of new preventative, diagnostic and therapeutic strategies that will ultimately contribute to the advancement of women's health. This article provides an overview on women-specific routes for the administration of drugs, focusing on aspects such as biological features pertaining to drug delivery, relevance in current clinical practice, available drug dosage forms/delivery systems and administration techniques, as well as recent trends in the field.

Multipurpose Prevention Technologies: Oral, Parenteral, and Vaginal Dosage Forms for Prevention of HIV/STIs and Unplanned Pregnancy

There is a high global prevalence of HIV, sexually transmitted infections (STIs), and unplanned pregnancies. Current preventative daily oral dosing regimens can be ineffective due to low patient adherence. Sustained release delivery systems in conjunction with multipurpose prevention technologies (MPTs) can reduce high rates of HIV/STIs and unplanned pregnancies in an all-in-one efficacious, acceptable, and easily accessible technology to allow for prolonged release of antivirals and contraceptives. The concept and development of MPTs have greatly progressed over the past decade and demonstrate efficacious technologies that are user-accepted with potentially high adherence. This review gives a comprehensive overview of the latest oral, parenteral, and vaginally delivered MPTs in development as well as drug delivery formulations with the potential to advance as an MPT, and implementation studies regarding MPT user acceptability and adherence. Furthermore, there is a focus on MPT intravaginal rings emphasizing injection molding and hot-melt extrusion manufacturing limitations and emerging fabrication advancements. Lastly, formulation development considerations and limitations are discussed, such as nonhormonal contraceptive considerations, challenges with achieving a stable coformulation of multiple drugs, achieving sustained and controlled drug release, limiting drug-drug interactions, and advancing past preclinical development stages. Despite the challenges in the MPT landscape, these technologies demonstrate the potential to bridge gaps in preventative sexual and reproductive health care.

Efficacy of silk fibroin biomaterial vehicle for in vivo mucosal delivery of Griffithsin and protection against HIV and SHIV infection ex vivo

Introduction

The majority of new HIV infections occur through mucosal transmission. The availability of readily applicable and accessible platforms for anti‐retroviral (ARV) delivery is critical for the prevention of HIV acquisition through sexual transmission in both women and men. There is a compelling need for developing new topical delivery systems that have advantages over the pills, gels and rings, which currently fail to guarantee protection against mucosal viral transmission in vulnerable populations due to lack of user compliance. The silk fibroin (SF) platform offers another option that may be better suited to individual circumstances and preferences to increase efficacy through user compliance. The objective of this study was to test safety and efficacy of SF for anti‐HIV drug delivery to mucosal sites and for viral prevention.

Methods

We formulated a potent HIV inhibitor Griffithsin (Grft) in a mucoadhesive silk fibroin (SF) drug delivery platform and tested the application in a non‐human primate model in vivo and a pre‐clinical human cervical and colorectal tissue explant model. Both vaginal and rectal compartments were assessed in rhesus macaques (Mucaca mulatta) that received SF (n = 4), no SF (n = 7) and SF‐Grft (n = 11). In this study, we evaluated the composition of local microbiota, inflammatory cytokine production, histopathological changes in the vaginal and rectal compartments and mucosal protection after ex vivo SHIV challenge.

Results

Effective Grft release and retention in mucosal tissues from the SF‐Grft platform resulted in protection against HIV in human cervical and colorectal tissue as well as against SHIV challenge in both rhesus macaque vaginal and rectal tissues. Mucoadhesion of SF‐Grft inserts did not cause any inflammatory responses or changes in local microbiota.

Conclusions

We demonstrated that in vivo delivery of SF‐Grft in rhesus macaques fully protects against SHIV challenge ex vivo after two hours of application and is safe to use in both the vaginal and rectal compartments. Our study provides support for the development of silk fibroin as a highly promising, user‐friendly HIV prevention modality to address the global disparity in HIV infection.

Lactoferrin nanoparticles coencapsulated with curcumin and tenofovir improve vaginal defense against HIV-1 infection

Aim: We report here the development of tenofovir- and curcumin-loaded lactoferrin nanoparticles (TCNPs) as an HIV-microbicide. Materials & methods: TCNPs were subjected to various physicochemical characterization experiments, followed by in vitro and in vivo experiments to assess their efficacy. Results: TCNPs had a diameter of 74.31 ± 2.56 nm with a gross encapsulation of more than 61% for each drug. Nanoparticles were effective against HIV-1 replication, with an IC₅₀ of 1.75 μM for curcumin and 2.8 μM for tenofovir. TCNPs provided drug release at the application site for up to 8-12 h, with minimal leakage into the systemic circulation. TCNPs showed spermicidal activity at ≥200 μM and induced minimal cytotoxicity and inflammation in the vaginal epithelium as revealed by histopathological and ELISA studies. Conclusion: We demonstrated that TCNPs could serve as a novel anti-HIV microbicidal agent in rats. [Formula: see text].

Design strategies for long-acting anti-HIV pharmaceuticals

Current combination antiretroviral therapy (cART) for human immunodeficiency virus (HIV) is limited by the frequent dosing and unfavorable adherence, and the rapid appearance of resistant mutants. Thus, there is a continuous need to improve and optimize the present therapies. The clinical phase III trials of FLAIR and ATLAS, showed two-drug injectable cabotegravir (CAB) and rilpivirine (RPV) formulation is potent, safe, and tolerable in HIV-infected patients. The recent approval of cabenuva (CAB+RPV) by Health Canada is a milestone in the development of long-term therapies for HIV infection. Broadly neutralizing antibodies (bNAbs) with excellent breath and efficiency against HIV have been investigated as LA antiviral weapons. Several modern modalities capable of sustained drug release for long-term treatment and prevention of HIV infection are also in development, such as implants, vaginal rings, and nanotherapies.

Co-crystals, Salts or Mixtures of Both? The Case of Tenofovir Alafenamide Fumarates

Tenofovir alafenamide fumarate (TAF) is the newest prodrug of tenofovir that constitutes several drug products used for the treatment of HIV/AIDS. Although the solid-state properties of its predecessor tenofovir disoproxil fumarate have been investigated and described in the literature, there are no data in the scientific literature on the solid state properties of TAF. In our report, we describe the preparation of two novel polymorphs II and III of tenofovir alafenamide monofumarate (TA MF2 and TA MF3). The solid-state structure of these compounds was investigated in parallel to the previously known tenofovir alafenamide monofumarate form I (TA MF1) and tenofovir alafenamide hemifumarate (TA HF). Interestingly, the single-crystal X-ray diffraction of TA HF revealed that this derivative exists as a co-crystal form. In addition, we prepared a crystalline tenofovir alafenamide free base (TA) and its hydrochloride salt (TA HCl), which enabled us to determine the structure of TA MF derivatives using ¹⁵N-ssNMR (¹⁵N-solid state nuclear magnetic resonance). Surprisingly, we observed that TA MF1 exists as a mixed ionization state complex or pure salt, while TA MF2 and TA MF3 can be obtained as pure co-crystal forms.

The application of nanomaterial science in the formulation a novel antibiotic: Assessment of the antifungal properties of mucoadhesive clotrimazole loaded nanofiber versus vaginal films

Candidiasis is the origin of several chronic diseases and causes a wide range of symptoms from mucosal to systemic and deadly infections. Vaginal patches are one of the best drug delivery systems for the treatment of fungal infections in the vaginal environment, so a mucoadhesive film containing drugs such as clotrimazole and metronidazole is commercially available for patients. In the present study, a physicochemical comparison is made between clotrimazole loaded film and nanofiber fabricated with the new hybrid mucoadhesive formulation of dextran and alginate. Toxicity testing was performed using the MTT assay. Bioadhesion and antifungal effects were investigated for fibers and films. The release behavior of clotrimazole from two systems was evaluated by Franz cell in each case. The most important difference between nanofibrous and film mats were obtained in antifungal, mucoadhesive, Young's modulus and morphology. The nanofiber has a higher antifungal effect and two-fold adhesive to the mouse tissue, than film. The inherent flexibility of nanofiber obviated the need for a plasticizer, which may have cytotoxic side effects. The Clotrimazole loaded nanofibrous of Alginate/Dextran mats were successfully electrospun. They exhibited more bioadhesive with higher and faster antifungal properties versus similar formulation film. Further in vivo investigation is required for their application in vaginal candidiasis.