Lipophilic nanocrystal prodrug-release defines the extended pharmacokinetic profiles of a year-long cabotegravir

An Ultra-Long-Acting Dimeric Bictegravir Prodrug Defined by a Short Pharmacokinetic Tail

Ultra-long-acting (ULA) antiretroviral parenteral formulations, with low injection volumes, high resistance barriers, and short pharmacokinetic (PK) tails, can transform HIV-1 therapeutics. Here, we converted bictegravir (BIC), a potent daily oral antiretroviral drug, into monomeric and homodimeric ester prodrugs. The homodimeric prodrug nanosuspension, NMXBIC, shows sustained plasma BIC levels >16 times the protein-adjusted 95% inhibitory concentration (PA-IC95) for six months after a single injection in Sprague Dawley rats. The results paralleled a short PK tail with the potential for late dose forgiveness. The monomeric prodrug nanosuspension, NM2BIC, shows lower year-long plasma BIC concentrations above PA-IC95 after a single injection in Sprague Dawley rats. After repeated injections, NMXBIC and NM2BIC are well tolerated in New Zealand White rabbits. NMXBIC's physicochemical properties and high BIC loading/unit mass of the prodrug contribute to its unique ULA PK profile. These results support its development as a ULA formulation for HIV-1 treatment and prevention.

The development of paliperidone nanocrystals for the treatment of schizophrenia

Schizophrenia is a complex and chronic psychiatric disorder that significantly impacts patients' quality of life. Ranking 12th among 310 diseases and injuries that result in disability, the number of patients suffering from schizophrenia continues to rise, emphasizing the urgent need for developing effective treatments. Despite the availability of effective antipsychotic drugs, over 80% of patients taking oral antipsychotics experience relapses, primarily caused by non-adherence as the high dosing frequency is required. In this review, we discuss about schizophrenia, its incidence, pathological causes, influencing factors, and the challenges of the current medications. Specifically, we explore nanocrystal technology and its application to paliperidone, making it one of the most successful long-acting antipsychotic drugs introduced to the market. We highlight the clinical advantages of paliperidone nanocrystals, including improved adherence, efficacy, long-term outcomes, patient satisfaction, safety, and cost-effectiveness. Additionally, we address the physicochemical factors influencing the drug's half-life, which crucially contribute to long-acting medications. Further studies on nanocrystal-based long-acting medications are crucial for enhancing their effectiveness and reliability. The successful development of paliperidone nanocrystals holds great promise as a significant approach for drug development, with potential applications for other chronic disease management.

Drug nanocrystals: Surface engineering and its applications in targeted delivery

Drug nanocrystals have received significant attention in drug development due to their enhanced dissolution rate and improved water solubility, making them effective in overcoming issues related to drug hydrophobicity, thereby improving drug bioavailability and treatment effectiveness. Recent advances in preparation techniques have facilitated research on drug surface properties, leading to valuable surface engineering strategies. Surface modification can stabilize drug nanocrystals, making them suitable for versatile drug delivery platforms. Functionalized ligands further enhance the potential for targeted delivery, enabling precision medicine. This review focuses on the surface engineering of drug nanocrystals, discussing various preparation methods, surface ligand design strategies, and their applications in targeted drug delivery, especially for cancer treatments. Finally, challenges and future directions are also discussed to promote the development of drug nanocrystals. The surface engineering of drug nanocrystals promises new opportunities for treating complex and chronic diseases while broadening the application of drug delivery systems.

New Therapies and Strategies to Curb HIV Infections with a Focus on Macrophages and Reservoirs

More than 80 million people worldwide have been infected with the human immunodeficiency virus (HIV). There are now approximately 39 million individuals living with HIV/acquired immunodeficiency syndrome (AIDS). Although treatments against HIV infection are available, AIDS remains a serious disease. Combination antiretroviral therapy (cART), also known as highly active antiretroviral therapy (HAART), consists of treatment with a combination of several antiretroviral drugs that block multiple stages in the virus replication cycle. However, the increasing usage of cART is inevitably associated with the emergence of HIV drug resistance. In addition, the development of persistent cellular reservoirs of latent HIV is a critical obstacle to viral eradication since viral rebound takes place once anti-retroviral therapy (ART) is interrupted. Thus, several efforts are being applied to new generations of drugs, vaccines and new types of cART. In this review, we summarize the antiviral therapies used for the treatment of HIV/AIDS, both as individual agents and as combination therapies, and highlight the role of both macrophages and HIV cellular reservoirs and the most recent clinical studies related to this disease.

Carrier-Free, Amorphous Verteporfin Nanodrug for Enhanced Photodynamic Cancer Therapy and Brain Drug Delivery

Glioblastoma (GBM) is hard to treat due to cellular invasion into functioning brain tissues, limited drug delivery, and evolved treatment resistance. Recurrence is nearly universal even after surgery, chemotherapy, and radiation. Photodynamic therapy (PDT) involves photosensitizer administration followed by light activation to generate reactive oxygen species at tumor sites, thereby killing cells or inducing biological changes. PDT can ablate unresectable GBM and sensitize tumors to chemotherapy. Verteporfin (VP) is a promising photosensitizer that relies on liposomal carriers for clinical use. While lipids increase VP's solubility, they also reduce intracellular photosensitizer accumulation. Here, a pure-drug nanoformulation of VP, termed "NanoVP", eliminating the need for lipids, excipients, or stabilizers is reported. NanoVP has a tunable size (65-150 nm) and 1500-fold higher photosensitizer loading capacity than liposomal VP. NanoVP shows a 2-fold increase in photosensitizer uptake and superior PDT efficacy in GBM cells compared to liposomal VP. In mouse models, NanoVP-PDT improved tumor control and extended animal survival, outperforming liposomal VP and 5-aminolevulinic acid (5-ALA). Moreover, low-dose NanoVP-PDT can safely open the blood-brain barrier, increasing drug accumulation in rat brains by 5.5-fold compared to 5-ALA. NanoVP is a new photosensitizer formulation that has the potential to facilitate PDT for the treatment of GBM.

Impact of the crystal size of crystalline active pharmaceutical compounds on loading into microneedles

Microneedle (MN) technology offers a promising platform for the delivery of a wide variety of active pharmaceutical compounds into and/or through the skin. Yet, the low loading capacity of MNs limits their clinical translation. The solid state of loaded compounds, crystallinity versus amorphousness and crystal size of the former, could greatly affect their loading. Here, we investigated the effect of the crystal size of crystalline compounds on their loading into dissolving MNs, prepared using the solvent-casting technique. A model crystalline compound was subjected to crystal size reduction via wet bead milling and loaded into dissolving MNs. A range of crystal sizes, from micro to nano, was obtained via different milling periods. The obtained crystals were characterized for their size, morphology, and sedimentation behavior. Besides, their content, solid state inside the MNs, and impact on the MN mechanical strength were assessed. The crystals exhibited size-dependent sedimentation, which dramatically affected their loading inside the MNs. However, crystal size and sedimentation demonstrated a negligible effect on the mechanical strength and sharpness of the needles, hence no anticipated impact on the MNs' drug delivery efficiency. The elucidation of the correlation between the crystal size and MN loading opens new potentials to address a major drawback in MN technology.

Recent advances of nanocrystals in cancer theranostics

Emerging cancer cases across the globe and treating them with conventional therapies with multiple limitations have been challenging for decades. Novel drug delivery systems and alternative theranostics are required for efficient detection and treatment. Nanocrystals (NCs) have been established as a significant cancer diagnosis and therapeutic tool due to their ability to deliver poorly water-soluble drugs with sustained release, low toxicity, and flexibility in the route of administration, long-term sustainable drug release, and noncomplicated excretion. This review summarizes several therapies of NCs, including anticancer, immunotherapy, radiotherapy, biotheranostics, targeted therapy, photothermal, and photodynamic. Further, different imaging and diagnostics using NCs are mentioned, including imaging, diagnosis through magnetic resonance imaging (MRI), computed tomography (CT), biosensing, and luminescence. In addition, the limitations and potential solutions of NCs in the field of cancer theranostics are discussed. Preclinical and clinical data depicting the importance of NCs in the spotlight of cancer, its current status, future aspects, and challenges are covered in detail.

Treatment of hepatitis delta and HIV infection

Hepatitis delta virus (HDV) is a defective agent that only infects individuals with hepatitis B virus (HBV). Around 5-10% of chronic hepatitis B patients worldwide are superinfected with HDV, which means 15-25 million people. Hepatitis delta is the most severe of all chronic viral hepatitis, leading to cirrhosis, liver cancer and/or transplantation in most patients. Despite it, many HDV patients remain undiagnosed. The only treatment available until recently was peginterferon alfa, with poor results and significant side effects. The recent approval of bulevirtide, a lipopeptide that blocks HBV/HDV entry, has revolutionized the field. Another drug, lonafarnib, already approved to treat progeria, is expected to be available soon as HDV therapy. Since there is no cell reservoir for the HDV RNA genome, hypothetically viral clearance could be achieved if complete blocking of viral replication occurs for a minimum time frame. This is what happens in hepatitis C using direct-acting antivirals, with the achievement of cure in nearly all treated patients. We envision the cure of hepatitis delta using combination antiviral therapy. Given that sexual and parenteral transmission routes are the most frequent for the acquisition of HBV and HDV, shared with HIV infection and HBV/HDV and HIV coinfection. The clinical outcome of hepatitis delta is worst in the HIV setting, with more frequent liver complications. Since most persons infected with HIV are on regular health care follow-up, we propose that HIV-HDV patients should be prioritized for moving forward new and potentially curative treatments for hepatitis delta.

Long-acting Parenteral Drug Delivery Systems for the Treatment of Chronic Diseases

The management of chronic conditions often requires patients to take daily medication for an extended duration. However, the need for daily dosing can lead to nonadherence to the therapy, which can result in the recurrence of the disease. Long-acting parenteral drug delivery systems have the potential to improve the treatment of chronic conditions. These systems use various technologies, such as oil-based injectables, PLGA-based microspheres, and in situ forming gel-based depots, to deliver different types of drugs. The use of long-acting parenteral formulations for the treatment of chronic infections such as HIV/AIDS and tuberculosis is a recent development in the field. Researchers are also exploring the use of long-acting parenteral formulations for the treatment of malaria, with the aim of reducing dosing frequency and improving adherence to treatment. This review discusses various aspects of long-acting formulation development, including the impact of the physicochemical properties of the drug, the type of long-acting formulation, and the route of administration. The clinical significance of long-acting formulations and recent advances in the field, such as long-acting nanoformulations and long-acting products currently in clinical trials, have also been highlighted.

Nanotherapeutic Approaches to Treat COVID-19-Induced Pulmonary Fibrosis

There have been significant collaborative efforts over the past three years to develop therapies against COVID-19. During this journey, there has also been a lot of focus on understanding at-risk groups of patients who either have pre-existing conditions or have developed concomitant health conditions due to the impact of COVID-19 on the immune system. There was a high incidence of COVID-19-induced pulmonary fibrosis (PF) observed in patients. PF can cause significant morbidity and long-term disability and lead to death in the long run. Additionally, being a progressive disease, PF can also impact the patient for a long time after COVID infection and affect the overall quality of life. Although current therapies are being used as the mainstay for treating PF, there is no therapy specifically for COVID-induced PF. As observed in the treatment of other diseases, nanomedicine can show significant promise in overcoming the limitations of current anti-PF therapies. In this review, we summarize the efforts reported by various groups to develop nanomedicine therapeutics to treat COVID-induced PF. These therapies can potentially offer benefits in terms of targeted drug delivery to lungs, reduced toxicity, and ease of administration. Some of the nanotherapeutic approaches may provide benefits in terms of reduced immunogenicity owing to the tailored biological composition of the carrier as per the patient needs. In this review, we discuss cellular membrane-based nanodecoys, extracellular vesicles such as exosomes, and other nanoparticle-based approaches for potential treatment of COVID-induced PF.

Formulation of antiretroviral nanocrystals and development into a microneedle delivery system for potential treatment of HIV-associated neurocognitive disorder (HAND)

HIV/AIDS remains a major global public health issue. While antiretroviral therapy is effective at reducing the viral load in the blood, up to 50% of those with HIV suffer from some degree of HIV-associated neurocognitive disorder, due to the presence of the blood-brain barrier restricting drugs from crossing into the central nervous system and treating the viral reservoir there. One way to circumvent this is the nose-to-brain pathway. This pathway can also be accessed via a facial intradermal injection. Certain parameters can increase delivery via this route, including using nanoparticles with a positive zeta potential and an effective diameter of 200 nm or less. Microneedle arrays offer a minimally invasive, pain-free alternative to traditional hypodermic injections. This study shows the formulation of nanocrystals of both rilpivirine (RPV) and cabotegravir, followed by incorporation into separate microneedle delivery systems for application to either side of the face. Following an in vivo study in rats, delivery to the brain was seen for both drugs. For RPV, a C_max was seen at 21 days of 619.17 ± 73.32 ng/g, above that of recognised plasma IC90 levels, and potentially therapeutically relevant levels were maintained for 28 days. For CAB, a C_max was seen at 28 days of 478.31 ± 320.86 ng/g, and while below recognised 4IC90 levels, does indicate that therapeutically relevant levels could be achieved by manipulating final microaaray patch size in humans.

Nanosuspensions technology as a master key for nature products drug delivery and In vivo fate

The drug nanosuspensions is a universal formulation approach for improved drug delivery of hydrophobic drugs and one the most promising approaches for increasing the biopharmaceutical performance of poorly water-soluble drug substances, especially for nature products. This review aimed to summarize the nanosuspensions preparation approaches and the main technological difficulties encountered in nanosuspensions development, such as guidelines for stabilizers screening, in vivo fate of the intravenously administrated nanosuspensions, and how to realize the intravenously target delivery was reviewed. Furthermore, challenges of nanosuspensions for the nature products delivery also was discussed and commented. Therefore, it hoped to provide reference and assistance for the nanosuspensions production, stabilizers usage, and predictability of in vivo fate and controllability of targeting delivery of the nature products nanosuspensions.

Pharmacokinetics of Long-Acting Aqueous Nano-/Microsuspensions After Intramuscular Administration in Different Animal Species and Humans-a Review

Formulating aqueous suspensions is an attractive strategy to incorporate poorly water-soluble drugs, where the drug release can be tailored to maintain desired release profiles of several weeks to months after parenteral (i.e., intramuscular or subcutaneous) administration. A sustained drug release can be desirable to combat chronic diseases by overcoming pill fatigue of a daily oral intake, hence, improving patient compliance. Although the marketed aqueous suspensions for intramuscular injection efficiently relieve the daily pill burden in chronic diseases, the exact drug release mechanisms remain to be fully unraveled. The in vivo drug release and subsequent absorption to the systemic circulation are influenced by a plethora of variables, resulting in a complex in vivo behavior of aqueous suspensions after intramuscular administration. A better understanding of the factors influencing the in vivo performance of aqueous suspensions could advance their drug development. An overview of the potential influential variables on the drug release after intramuscular injection of aqueous suspensions is provided with, where possible, available pharmacokinetic parameters in humans or other species derived from literature, patents, and clinical trials. These variables can be categorized into drug substance and formulation properties, administration site properties, and the host response towards drug particles. Based on the findings, the most critical factors are particle size, dose level, stabilizing excipient, drug lipophilicity, gender, body mass index, and host response.

Long-acting HIV Pre-exposure Prophylaxis (PrEP) approaches: Recent advances, emerging technologies and development challenges

Introduction:

Poor or inconsistent adherence to daily oral pre-exposure prophylaxis (PrEP) has emerged as a key barrier to effective HIV prevention. The advent of potent long-acting (LA) antiretrovirals (ARVs) in conjunction with advances in controlled release technologies has enabled LA ARV drug delivery systems (DDS) capable of providing extended dosing intervals and overcome the challenge of suboptimal drug adherence with daily oral dosing.

Areas covered:

This review discusses the current state of the LA PrEP field, recent advances, and emerging technologies, including ARV prodrug modifications and new DDS. Technological challenges, knowledge gaps, preclinical testing considerations, and future directions important in the context of clinical translation and implementation of LA HIV PrEP are discussed.

Expert opinion:

The HIV prevention field is evolving faster than ever and the bar for developing next-generation LA HIV prevention options continues to rise. The requirements for viable LA PrEP products to be implemented in resource-limited settings are challenging, necessitating proactive consideration and product modifications during the design and testing of promising new candidates. If successfully translated, next-generation LA PrEP that are safe, affordable, highly effective, and accepted by both end-users and key stakeholders will offer significant potential to curb the HIV pandemic.

Microcrystals of Ketal-Linked Paliperidone Prodrugs for Long-Acting Antipsychotics

Intramuscularly injectable long-acting prodrug-based microcrystals (MCs) are of particular interest for chronic disease management. Nevertheless, current prevalently used linkers degraded by enzymes have the potential drawback of substantial differences in enzyme levels between individuals. Here, we reported the synthesis of a stearyl-modified paliperidone prodrug (SKP) with an acid-sensitive ketal linker for developing long-acting MC antipsychotics. SKP-MCs of three different sizes were prepared and systematically examined. We found that paliperidone exposure in SKP-MC-treated rats was prolonged compared with that in rats treated with the commercial antipsychotic Invega Sustenna and that the drug release rate decreased with increasing MC size. In inflammation-inhibition-model rats, paliperidone release from the SKP-MCs was considerably decreased, indicating that the immune-mediated foreign-body response after intramuscular administration boosted paliperidone release. Our findings will provide valuable insights into in vivo drug release from prodrug-based MC formulations. The ketal-linked prodrug strategy might be a new solution for developing long-acting prodrug formulations of hydroxyl-group-bearing drugs.

Pre-Exposure Prophylaxis for viral infections other than HIV

The battle against human viral infections has historically relied on two medical strategies, namely vaccines to protect from contagion and antivirals to treat infected patients. In the absence of vaccines, antivirals have occasionally been used as peri-exposure prophylaxis, given either before (pre-exposure prophylaxis) or right after (post-exposure prophylaxis). In an unprecedented way, the use of antiretrovirals as chemoprophylaxis has triumphed in the HIV field. Indeed, oral antiretrovirals given either daily or at demand to HIV-uninfected individuals engaged in high-risk behaviors protect from contagion. More recently, the advent of long-acting formulations has allowed HIV protection following intramuscular injections every three months. Can we envision a similar prophylactic strategy for other human viral infections? The advent of such 'chemical vaccines' would fill an unmet need when classical vaccines do not exist, cannot be recommended, immune responses are suboptimal, escape mutants emerge or immunity wanes. In this review, we discuss the opportunities for antiviral chemoprophylaxis for viral hepatitis B and C, retroviruses HTLV-1 and HIV-2, and respiratory viruses influenza and SARS-CoV-2, among others.

Nanocrystals for controlled delivery: State of the art and approved drug products

INTRODUCTION

Controlled/extended-release formulations offer numerous benefits over conventional especially reduced side effects, improved therapeutic outcomes and high patient compliance. Controlled release nanocrystal is extremely versatile technology with several advantages such as very high drug loading, ease of manufacturing, avoidance of dose dumping, reproducible drug release. Usually, nanonization of drug is performed to improve dissolution rate, intrinsic solubility and thereby bioavailability. Most of the times, this is done for immediate release dosage forms where objective is quick onset of action. However, nanocrystals can also provide a sustained, reproducible plasma concentration profile for weeks to months based on tissue microenvironment, surface coating administration route.

AREAS COVERED

This review briefly describes the methods for producing nanocrystals, summarizes preclinical research and commercial products demonstrating tremendous potential of controlled release nanocrystals.

EXPERT OPINION

Lipophilic drugs are attractive candidates for the development of nanocrystal based controlled release formulations. However, constraint should be practiced while generalizing the technology for the controlled release purpose. Not all drugs fit in the requirement from the perspectives of physicochemical properties or pharmacokinetic requirements. Additionally, technologies should be explored which can convert the nanocrystal into its final dosage form for administration yet preserves the benefits of small particle size and controlled release.

Real-Life Therapeutic Concentration Monitoring of Long-Acting Cabotegravir and Rilpivirine: Preliminary Results of an Ongoing Prospective Observational Study in Switzerland

SHCS#879 is an ongoing Switzerland-wide multicenter observational study conducted within the Swiss HIV Cohort Study (SHCS) for the prospective follow-up of people living with HIV (PLWH) receiving long-acting injectable cabotegravir-rilpivirine (LAI-CAB/RPV). All adults under LAI-CAB/RPV and part of SHCS are enrolled in the project. The study addresses an integrated strategy of treatment monitoring outside the stringent frame of controlled clinical trials, based on relevant patient characteristics, clinical factors, potential drug-drug interactions, and measurement of circulating blood concentrations. So far, 91 blood samples from 46 PLWH have been collected. Most individuals are less than 50 years old, with relatively few comorbidities and comedications. The observed concentrations are globally in accordance with the available values reported in the randomized clinical trials. Yet, low RPV concentrations not exceeding twice the reported protein-adjusted 90% inhibitory concentration have been observed. Data available at present confirm a considerable between-patient variability overall. Based on the growing amount of PK data accumulated during this ongoing study, population pharmacokinetic analysis will characterize individual concentration-time profiles of LAI-CAB/RPV along with their variability in a real-life setting and their association with treatment response and tolerability, thus bringing key data for therapeutic monitoring and precision dosage adjustment of this novel long-acting therapy.

The future of long-acting agents for preexposure prophylaxis

PURPOSE OF REVIEW

The main reason for the failure of oral preexposure prophylaxis (PrEP) regimens for HIV is poor adherence. Intramuscular cabotegravir was recently approved for PrEP, and a number of other long-acting antiretroviral formulations and products are currently in clinical development. This includes subcutaneous and intravenous injections, implants, and microarray (microneedle) patches, as well as extended duration oral drugs. The success and future uptake of these products will depend on a variety of factors.

RECENT FINDINGS

Long-acting delivery of antiretroviral agents for PrEP confers significant advantages over short-acting oral delivery. This is exemplified by the superior efficacy of intramuscular cabotegravir given every eight weeks as compared to daily oral co-formulated tenofovir disoproxil fumarate and emtricitabine. There is also evidence for PrEP efficacy for a broadly neutralizing monoclonal antibody given intravenously every eight weeks. One of the leading candidates for long-acting PrEP, islatravir, was being studied as a monthly oral drug or a nonerodable subcutaneous implant inserted for up to 12 months. However, clinical studies of this agent were put on hold in late 2021 because of unanticipated lymphopenia.

SUMMARY

Long-acting antiretroviral products have substantial promise for PrEP and have particular advantages over daily oral drugs based mainly on improved adherence. However, there are barriers to further uptake that include the need for more intensive interaction with systems of healthcare delivery, greater expense and complexity of implementation, and unexpected long-term toxicities.

Towards the Antiviral Agents and Nanotechnology-Enabled Approaches Against Parvovirus B19

Parvovirus B19 (B19V) as a human pathogenic virus, would cause a wide range of clinical manifestations. Besides the supportive and symptomatic treatments, the only FDA-approved antiviral drug for the treatment of B19V is intravenous immunoglobulins, which however, have limited efficacy and high cost. By far, there are still no virus-specific therapeutics clinically available to treat B19V infection. Therefore, exploiting the potential targets with a deep understanding of the life cycle of B19V, are pivotal to the development of B19V-tailored effective antiviral approaches. This review will introduce antiviral agents via blocking viral invasion, inhibiting the enzymes or regulatory proteins involved in DNA synthesis, and so on. Moreover, nanotechnology-enabled approaches against B19V will also be outlined and discussed through a multidisciplinary perspective involving virology, nanotechnology, medicine, pharmaceutics, chemistry, materials science, and other fields. Lastly, the prospects of the antiviral agents and nanosystems in terms of fabrication, clinical translation and potential breakthroughs will be briefly discussed.

Transformation of dolutegravir into an ultra-long-acting parenteral prodrug formulation

Ultra-long-acting integrase strand transfer inhibitors were created by screening a library of monomeric and dimeric dolutegravir (DTG) prodrug nanoformulations. This led to an 18-carbon chain modified ester prodrug nanocrystal (coined NM2DTG) with the potential to sustain yearly dosing. Here, we show that the physiochemical and pharmacokinetic (PK) formulation properties facilitate slow drug release from tissue macrophage depot stores at the muscle injection site and adjacent lymphoid tissues following single parenteral injection. Significant plasma drug levels are recorded up to a year following injection. Tissue sites for prodrug hydrolysis are dependent on nanocrystal dissolution and prodrug release, drug-depot volume, perfusion, and cell-tissue pH. Each affect an extended NM2DTG apparent half-life recorded by PK parameters. The NM2DTG product can impact therapeutic adherence, tolerability, and access of a widely used integrase inhibitor in both resource limited and rich settings to reduce HIV-1 transmission and achieve optimal treatment outcomes.

Ultra-long-acting antivirals as chemical vaccines to prevent viral diseases

For two centuries, vaccines have been successful in the fight against viruses, triggering immune protection. Indeed, the elimination of smallpox, the only infectious disease eradicated to date, was made possible through vaccination. For measles, polio and hepatitis B, vaccines are available but significant challenges exist for universal coverage. For other viruses, such as HIV and hepatitis C, vaccines have remained elusive. Recent advances in medicinal chemistry have resulted in the production of antivirals that can extend activity for months. We envision the use of ultra-long-acting antivirals for the prevention of certain viral illnesses, halting either contagions or reactivations under immunosuppression. Such 'chemical vaccines' would fill an immediate need in providing protection when classic vaccines do not exist, responses are suboptimal, escape mutants emerge or immunity wanes.

Analyte recovery in LC-MS/MS bioanalysis: An old issue revisited

There are several challenges associated with LC-MS/MS bioanalytical method development and validation. Low and variable recovery of some analytes, especially the more hydrophobic ones, is often challenging. Analytes can be lost to various extents throughout the process of sample collection, storage, before, during, and/or after sample preparation and analysis. The calculation of overall extraction recovery can detect problems of low recovery during sample preparation but does not identify the source(s) of analyte losses. Low overall analyte recovery is the net result of losses that can happen for multiple reasons at all steps of sample preparation and analysis. Therefore, identifying the source(s) of analyte loss during sample preparation can help guide the optimization the bioanalysis conditions to minimize these losses. In this article we propose a practical protocol to systematically identify and quantify the sources of low analyte recovery. This allows the proper choice of strategies to optimize the relevant bioanalytical conditions to minimize analyte losses and improve overall recovery.

Non-Viral Vectors for Delivery of Nucleic Acid Therapies for Cancer

The research and development of non-viral gene therapy has been extensive over the past decade and has received a big push thanks to the recent successful approval of non-viral nucleic acid therapy products. Despite these developments, nucleic acid therapy applications in cancer have been limited. One of the main causes of this has been the imbalance in development of delivery vectors as compared with sophisticated nucleic acid payloads, such as siRNA, mRNA, etc. This paper reviews non-viral vectors that can be used to deliver nucleic acids for cancer treatment. It discusses various types of vectors and highlights their current applications. Additionally, it discusses a perspective on the current regulatory landscape to facilitate the commercial translation of gene therapy.

Oral antivirals for the prevention and treatment of SARS-CoV-2 infection

Vaccines and antivirals are the classical weapons deployed to contain, prevent, and treat life-threatening viral illnesses. Specifically, for SARS-CoV-2 infection, vaccines protect against severe COVID-19 disease manifestations and complications. However, waning immunity and emergence of vaccine escape mutants remains a growing threat. This is highlighted by the current surge of the omicron COVID-19 variant. Thus, there is a race to find treatment alternatives. We contend that oral small molecule antivirals that halt SARSCoV- 2 infection are essential. Compared to currently available monoclonal antibodies and remdesivir, where parenteral administration is required, oral antivirals offer treatments in an outpatient setting with dissemination available on a larger scale. In response to this need at 2021's end, regulatory agencies provided emergency use authorization for both molnupiravir and nirmatrelvir. These medicines act on the viral polymerase and protease, respectively. Each is given for 5 days and can reduce disease progression by 30% and 89%, respectively. The advent of additional oral antivirals, the assessment of combination therapies, the formulation of extended-release medications, and their benefit for both early treatment and prophylaxis will likely transform the landscape of the COVID-19 pandemic.

Prodrug Therapies for Infectious and Neurodegenerative Diseases

Prodrugs are bioreversible drug derivatives which are metabolized into a pharmacologically active drug following chemical or enzymatic modification. This approach is designed to overcome several obstacles that are faced by the parent drug in physiological conditions that include rapid drug metabolism, poor solubility, permeability, and suboptimal pharmacokinetic and pharmacodynamic profiles. These suboptimal physicochemical features can lead to rapid drug elimination, systemic toxicities, and limited drug-targeting to disease-affected tissue. Improving upon these properties can be accomplished by a prodrug design that includes the careful choosing of the promoiety, the linker, the prodrug synthesis, and targeting decorations. We now provide an overview of recent developments and applications of prodrugs for treating neurodegenerative, inflammatory, and infectious diseases. Disease interplay reflects that microbial infections and consequent inflammation affects neurodegenerative diseases and vice versa, independent of aging. Given the high prevalence, personal, social, and economic burden of both infectious and neurodegenerative disorders, therapeutic improvements are immediately needed. Prodrugs are an important, and might be said a critical tool, in providing an avenue for effective drug therapy.

Evolution of drug delivery systems: From 1950 to 2020 and beyond

Modern drug delivery technology began in 1952 with the advent of the Spansule® sustained-release capsule technology, which can deliver a drug for 12 h after oral administration through an initial immediate dose followed by the remaining released gradually. Until the 1980s, oral and transdermal formulations providing therapeutic durations up to 24 h for small molecules dominated the drug delivery field and the market. The introduction of Lupron Depot® in 1989 opened the door for long-acting injectables and implantables, extending the drug delivery duration from days to months and occasionally years. Notably, the new technologies allowed long-term delivery of peptide and protein drugs, although limited to parenteral administration. The introduction of the first PEGylated protein, Adagen®, in 1990 marked the new era of PEGylation, resulting in Doxil® (doxorubicin in PEGylated liposome) in 1995, Movantik® (PEGylated naloxone - naloxegol) in 2014, and Onpattro® (Patisiran - siRNA in PEGylated lipid nanoparticle) in 2018. Drug-polymer complexes were introduced, e.g., InFed® (iron-dextran complex injection) in 1974 and Abraxane® (paclitaxel-albumin complex) in 2005. In 2000, both Mylotarg™ (antibody-drug conjugate - gemtuzumab ozogamicin) and Rapamune® (sirolimus nanocrystal formulation) were introduced. The year 2000 also marked the launching of the National Nanotechnology Initiative by the U.S. government, which was soon followed by the rest of the world. Extensive work on nanomedicine, particularly formulations designed to escape from endosomes after being taken by tumor cells, along with PEGylation technology, ultimately resulted in the timely development of lipid nanoparticle formulations for COVID-19 vaccine delivery in 2020. While the advances in drug delivery technologies for the last seven decades are breathtaking, they are only the tip of an iceberg of technologies that have yet to be utilized in an approved formulation or even to be discovered. As life expectancy continues to increase, more people require long-term care for various diseases. Filling the current and future unmet needs requires innovative drug delivery technologies to overcome age-old familiar hurdles, e.g., improving water-solubility of poorly soluble drugs, overcoming biological barriers, and developing more efficient long-acting depot formulations. The lessons learned from the past are essential assets for developing future drug delivery technologies implemented into products. As the development of COVID-19 vaccines demonstrated, meeting the unforeseen crisis of the uncertain future requires continuous cumulation of failures (as learning experiences), knowledge, and technologies. Conscious efforts of supporting diversified research topics in the drug delivery field are urgently needed more than ever.

Ultra-long-acting (XLA) antivirals for chronic viral hepatitis

Viral hepatitis is among the top four causes of mortality globally, causing 1.4 million deaths each year, exceeding tuberculosis, malaria and human immunodeficiency virus. Hepatitis B and C are responsible for 90% of hepatitis deaths, and the remaining 10% are caused by other hepatitis viruses. The annual number of deaths from hepatitis C is declining, whereas the numbers of deaths from hepatitis B and D are increasing. Hepatitis B alone represents the seven highest cause of mortality worldwide. Spurred on by development of curative antivirals for hepatitis C and expanding access to hepatitis B virus (HBV) vaccination, the World Health Organization has committed to eliminating viral hepatitis as a public health threat by 2030. Like the majority of current antivirals, those available for HBV are virostatic. They are capable of suppressing viral replication but cannot eliminate the virus from infected patients. Therefore, treatment is lifelong. Long-term adherence to medication continues to represent a major challenge. Importantly, HBV often reactivates, leading to potential life-threatening events in immunosuppressed patients. Therapeutic options are limited for hepatitis D; however, promising new, effective antivirals are on the horizon. Recent advances have emerged in medicinal chemistry and drug delivery approaches to produce ultra-long-acting (XLA) antivirals. These can extend antiviral activity from months to 1 year or even longer. These new formulations can overcome the challenges of daily dosing and maximize drug exposure. The development of XLA antivirals targeting viral hepatitis may also facilitate cure strategies.

Update and latest advances in antiretroviral therapy

Since the first cases of AIDS appeared in 1981, human immunodeficiency virus type 1 (HIV-1) infection has reached pandemic proportions. Forty years later, research has led to the approval of more than 30 antiretroviral drugs, while combination therapies have turned HIV-1 infection into a chronic, but manageable disease. Still, drug toxicity and acquired and transmitted drug resistance remain as major threats to therapy success. In this review, we provide an overview on currently available anti-HIV drugs and the latest developments in antiretroviral therapy, focused on new antiretroviral agents acting on known and unexploited antiviral targets, prevention therapies aimed to improve available drug combinations, and research on new long-acting therapies, particularly those involving novel drug candidates such as lenacapavir or islatravir.

Rational Design of Thermosensitive Hydrogel to Deliver Nanocrystals with Intranasal Administration for Brain Targeting in Parkinson's Disease

Mitochondrial dysfunction is commonly detected in individuals suffering from Parkinson's disease (PD), presenting within the form of excessive reactive oxygen species (ROS) generation as well as energy metabolism. Overcoming this dysfunction within brain tissues is an effective approach to treat PD, while unluckily, the blood-brain barrier (BBB) substantially impedes intracerebral drug delivery. In an effort to improve the delivery of efficacious therapeutic drugs to the brain, a drug delivery platform hydrogel (MAG-NCs@Gel) was designed by complexing magnolol (MAG)-nanocrystals (MAG-NCs) into the noninvasive thermosensitive poly(N-isopropylacrylamide) (PNIPAM) with self-gelation. The as-prepared MAG-NCs@Gel exhibited obvious improvements in drug solubility, the duration of residence with the nasal cavity, and the efficiency of brain targeting, respectively. Above all, continuous intranasal MAG-NCs@Gel delivery enabled MAG to cross the BBB and enter dopaminergic neurons, thereby effectively alleviating the symptoms of MPTP-induced PD. Taking advantage of the lower critical solution temperature (LCST) behavior of this delivery platform increases its viscoelasticity in nasal cavity, thus improving the efficiency of MAG-NCs transit across the BBB. As such, MAG-NCs@Gel represented an effective delivery platform capable of normalizing ROS and adenosine triphosphate (ATP) in the mitochondria of dopaminergic neurons, consequently reversing the mitochondrial dysfunction and enhancing the behavioral skills of PD mice without adversely affecting normal tissues.

Advances in long-acting injectables, implants, and vaginal rings for contraception and HIV prevention

Worldwide, women face compounding reproductive health risks, including human immunodeficiency virus (HIV), sexually-transmitted infections (STIs), and unintended pregnancy. Multipurpose prevention technologies (MPTs) offer combined protection against these overlapping risks in singular prevention products that offer potential for simplified use, lower burden, higher acceptability, and increased public health benefits. Over the past decade, substantial progress has been made in development of extended-release MPTs, which have further potential to grant sexual and reproductive health autonomy to women globally and to offer choice for women to accommodate varying needs during their reproductive lives. Here, we highlight the advances made in injectable, implant, and ring delivery forms, and the importance of incorporating end-user preferences early in the research and development of these products.

Ultra-long acting prodrug of dolutegravir and delivery system - Physicochemical, pharmacokinetic and formulation characterizations

The focus of present work was to characterize ultra-long acting prodrug of dolutegravir (DTG) and develop biodegradable microparticle formulation. Palmitic acid (PA) conjugated prodrug of DTG was prepared by esterification of hydroxyl group of DTG with the carboxyl group of PA. Physicochemical properties of the prodrug was characterize by MS, NMR, FTIR, SEM, DSC, NIR-CI, pH-solubility, and solid and liquid pH-stability. Comparative solid and liquid stability was performed by storing powder DTG and DTG-Palmitate at 40 °C/75% RH for three months and liquid solution pH 2-8 at room temperature for 24 h, respectively. Pharmacokinetic evaluation was performed in white albino New Zealand rabbits by subcutaneous injection (30 mg/Kg). Poly(lactide-co-glycolide) microparticle formulation was prepared by emulsification-evaporation method and characterized for particle size distribution, shape, drug loading and in-vitro release. MS, NMR, FTIR, SEM, DSC, NIR-CI indicated formation of prodrug. Melting point of the prodrug was lower than DTG but higher than PA. Shape of DTG crystals was irregular while DTG-Palmitate crystals was fine-needle. Solid and liquid stability profiles of the prodrug were similar to DTG. Plasma half-life, area under the curve, and mean-residence time of DTG-Palmitate were 8.8, 2.3 and 14.7 folds of DTG. D₉₀ of DTG and DTG-Palmitate microparticles was 107.1 ± 2.7 and 94.3 ± 3.4 µm, respectively. The in-vitro drug release was almost complete in three weeks from DTG microparticles while it was <85% in six months from DTG-Palmitate microparticles. In conclusion, physicochemical and pharmacokinetic properties and biodegradable microparticles of the prodrug suggested that the prodrug has potential of sustaining DTG release for ultra-long period compared to DTG.