Dry powder measles vaccine: particle deposition, virus replication, and immune response in cotton rats following inhalation

Inundative, Dry-Powder, Inhaled Measles Vaccination to Prevent Deaths of Young Children in War-torn Regions

Children living in war-torn and geographically remote regions often die from measles due to undervaccination. Protective community immunity could be safely improved through the comprehensive use of small, inexpensive, easy-to-use, dry-powder aerosolized measles vaccination inhalers. Influential local community members could be engaged to provide risk counseling and inform their peers of measles risks to inspire vaccine uptake. Vaccination by inhaled live attenuated measles vaccine has been shown to be safe and protective among several million research subjects and omits (1) needles, syringes, glass vials, and specialized disposal systems; (2) deadly vaccine reconstitution errors; (3) cold chain technology to protect temperature-sensitive vaccine; (4) vaccine wastage associated with suboptimal use of multidose vials; (5) trained vaccinators; (6) food, housing, and transportation costs associated with centralized vaccination campaigns; and (7) risk of violence to vaccinators and associated staff. All elements for inhaler-based measles vaccination are readily available. Dry-powder measles vaccine inhalers can be assembled and distributed to save lives.

Incentivized self-vaccination for global measles eradication

Measles-we've become inured to its cruel, insidious impact as it kills over 100,000 children yearly because of suboptimal vaccination coverage. It does not have to be this way. A familiar, safe, exceptionally effective measles vaccine saves lives and permanent, global measles eradication is within reach. But now we need to be clever and courageously explore new strategies to save lives. Firstly, let us enable people to vaccinate themselves, not with a needle and syringe, but with a quick inhaled puff of dry powder vaccine. Secondly, let us provide micro-payments using digital currency to incentivize those who vaccinate themselves. Thirdly, let us leverage learnings from how our social networks guide our behaviors to further encourage self-vaccination. Fourthly, let us inspire friendly regional competition among communities vying for the highest proportion of citizens who show measles neutralizing antibodies in spot saliva samples. With global cooperation and relentless determination, we eradicated smallpox. Next up? Measles.

Recent advances on chitosan as an adjuvant for vaccine delivery

Chitosan (CS) is a natural polymer derived from chitin that has wide applications in drugs, vaccines, and antigen delivery. The distinctive mucoadhesive, biocompatibility, biodegradable, and less toxic properties of chitosan compared to the currently used vaccine adjuvants made it a promising candidate for use as an adjuvant/carrier in vaccine delivery. In addition, chitosan exhibits intrinsic immunomodulating properties making it a suitable adjuvant in preparing vaccines delivery systems. Nanoparticles (NPs) of chitosan and its derivatives loaded with antigen have been shown to induce cellular and humoral responses. Versatility in the physicochemical properties of chitosan can provide an excellent opportunity to engineer antigen-specific adjuvant/delivery systems. This review discusses the recent advances of chitosan and its derivatives as adjuvants in vaccine deliveryand the published literature in the last fifteen years. The impact of physicochemical properties of chitosan on vaccine formulation has been described in detail. Applications of chitosan and its derivatives, their physicochemical properties, and mechanisms in enhancing immune responses have been discussed. Finally, challenges and future aspects of chitosan use has been pointed out.

Advancements in Particle Engineering for Inhalation Delivery of Small Molecules and Biotherapeutics

Dry powder inhalation formulations have become increasingly popular for local and systemic delivery of small molecules and biotherapeutics. Powder formulations provide distinct advantages over liquid formulations such as elimination of cold chain due to room temperature stability, improved portability, and the potential for increasing patient adherence. To become a viable product, it is essential to develop formulations that are stable (physically, chemically and/or biologically) and inhalable over the shelf-life. Physical particulate properties such as particle size, morphology and density, as well as chemical properties can significantly impact aerosol performance of the powder. This review will cover these critical attributes that can be engineered to enhance the dispersibility of inhalation powder formulations. Challenges in particle engineering for biotherapeutics will be assessed, followed by formulation strategies for overcoming the hurdles. Finally, the review will discuss recent examples of successful dry powder biotherapeutic formulations for inhalation delivery that have been clinically assessed.

Thermostability of Measles and Rubella Vaccines in a Microneedle Patch

Measles and rubella vaccinations are highly effective at reducing disease prevalence; however, logistic issues related to subcutaneous administration and vaccine wastage limit the extent of vaccination coverage. Microneedle (MN) patches can increase coverage by easing logistics through simplified administration and improved stability. This study demonstrates the thermostability of a bivalent measles and rubella vaccine MN patch. Rubella vaccine stability required pH buffering during drying; potassium phosphate buffer at neutral pH was optimal for both vaccines. Screening 43 excipients for their ability to retain potency during drying and storage yielded sucrose-threonine-potassium phosphate buffer formulation at pH 7.5 as an optimal formulation. MN patches made with this formulation had no significant loss of vaccine titer after one month and remained within a one log₁₀ titer loss cutoff after 3 - 4 months at 5°C, 25°C and 40°C. Finally, these patches were shown to be immunogenic in juvenile rhesus macaques. This work demonstrates the potential for MN patches for measles and rubella vaccination to be removed from the cold chain, which is expected to decrease vaccine cost and wastage, and increase vaccination coverage.

Solid Dosage Forms of Biopharmaceuticals in Drug Delivery Systems Using Sustainable Strategies

Drug delivery systems (DDS) often comprise biopharmaceuticals in aqueous form, making them susceptible to physical and chemical degradation, and therefore requiring low temperature storage in cold supply and distribution chains. Freeze-drying, spray-drying, and spray-freeze-drying are some of the techniques used to convert biopharmaceuticals-loaded DDS from aqueous to solid dosage forms. However, the risk exists that shear and heat stress during processing may provoke DDS damage and efficacy loss. Supercritical fluids (SCF), specifically, supercritical carbon dioxide (scCO₂), is a sustainable alternative to common techniques. Due to its moderately critical and tunable properties and thermodynamic behavior, scCO₂ has aroused scientific and industrial interest. Therefore, this article reviews scCO₂-based techniques used over the year in the production of solid biopharmaceutical dosage forms. Looking particularly at the use of scCO₂ in each of its potential roles—as a solvent, co-solvent, anti-solvent, or co-solute. It ends with a comparison between the compound’s stability using supercritical CO₂-assisted atomization/spray-drying and conventional drying.

Inhaled vaccine delivery in the combat against respiratory viruses: a 2021 overview of recent developments and implications for COVID-19

INTRODUCTION

As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care. Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses.

AREAS COVERED

Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy. We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible. The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar.

EXPERT OPINION

We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages. Firstly, their dry state can tremendously increase vaccine stability and shelf-life. Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns. Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.

Estimating the nationwide transmission risk of measles in US schools and impacts of vaccination and supplemental infection control strategies

BACKGROUND

The spread of airborne infectious diseases such as measles is a critical public health concern. The U.S. was certified measles-free in 2000, but the number of measles cases has increased in recent years breaking the record of the nationwide annual number of cases since 1992. Although the characteristics of schools have made them one of the most vulnerable environments during infection outbreaks, the transmission risk of measles among students is not completely understood. We aimed to evaluate how three factors influence measles transmission in schools: personal (vaccination), social (compartmentalizing), and building systems (ventilation, purification, and filtration).

METHODS

We used a combination of a newly developed multi-zone transient Wells-Riley approach, a nationwide representative School Building Archetype (SBA) model, and a Monte-Carlo simulation to estimate measles risk among U.S. students. We compared our risk results with the range of reported transmission rates of measles in school outbreaks to validate the risk model. We also investigated the effectiveness of vaccination and ten supplemental infection control scenarios for reducing the risk of measles transmission among students.

RESULTS

Our best nationwide estimate of measles transmission risk in U.S. schools were 3.5 and 32% among all (both unvaccinated and immunized) and unvaccinated students, respectively. The results showed the transmission risk of measles among unvaccinated students is > 70 times higher than properly immunized ones. We also demonstrated that the transmission risk of measles in primary schools (assuming teacher self-contained classrooms) is less than secondary schools (assuming departmentalized systems). For building-level interventions, schools with ductless-with-air-filter and ductless-without-air-filter systems have the lowest and highest transmission risks of measles, respectively. Finally, our simulation showed that infection control strategies could cut the average number of infected cases among all students in half when a combination of advanced air filtration, ventilation, and purification was adopted in the modeled schools.

CONCLUSIONS

Our results highlight the primary importance of vaccination for reducing the risk of measles transmission among students. Yet, additional and significant risk reduction can be achieved through compartmentalizing students and enhancing building ventilation and filtration systems.

Recent Approaches for Solid Dose Vaccine Delivery

Recent studies on vaccine delivery systems are exploring the possibility of replacing liquid vaccines with solid dose vaccines due to the many advantages that solid dose vaccines can offer. These include the prospect of a needle-free vaccine delivery system leading to better patient compliance, cold chain storage, less-trained vaccinators and fewer chances for needle stick injury hazards. Some studies also indicate that vaccines in a solid dosage form can result in a higher level of immunogenicity compared to the liquid form, thus providing a dose-sparing effect. This review outlines the different approaches in solid vaccine delivery using various routes of administration including, oral, pulmonary, intranasal, buccal, sublingual, and transdermal routes. The various techniques and their current advancements will provide a knowledge base for future work to be carried out in this arena.

Respiratory syncytial virus subunit vaccines based on the viral envelope glycoproteins intended for pregnant women and the elderly

Introduction: Respiratory syncytial virus (RSV) causes high morbidity and mortality rates among infants, young children, and the elderly worldwide. Unfortunately, a safe and effective vaccine is still unavailable. In 1966, a formalin-inactivated RSV vaccine failed and resulted in the death of two young children. This failure shifted research toward the development of subunit-based vaccines for pregnant women (to passively vaccinate infants) and the elderly. Among these subunit-based vaccines, the viral envelope glycoproteins show great potential as antigens. Areas covered: In this review, progress in the development of safe and effective subunit RSV vaccines based on the viral envelope glycoproteins and intended for pregnant women and the elderly, are reviewed and discussed. Studies published in the period 2012-2018 were included. Expert opinion: Researchers are close to bringing safe and effective subunit-based RSV vaccines to the market using the viral envelope glycoproteins as antigens. However, it remains a major challenge to elicit protective immunity, with a formulation that has sufficient (storage) stability. These issues may be overcome by using the RSV fusion protein in its pre-fusion conformation, and by formulating this protein as a dry powder. It may further be convenient to administer this powder via the pulmonary route.

Mucosal Vaccination via the Respiratory Tract

Vaccine delivery via mucosal surfaces is an interesting alternative to parenteral vaccine administration, as it avoids the use of a needle and syringe. Mucosal vaccine administration also targets the mucosal immune system, which is the largest lymphoid tissue in the human body. The mucosal immune response involves systemic, antigen-specific humoral and cellular immune response in addition to a local response which is characterised by a predominantly cytotoxic T cell response in combination with secreted IgA. This antibody facilitates pathogen recognition and deletion prior to entrance into the body. Hence, administration via the respiratory mucosa can be favoured for all pathogens which use the respiratory tract as entry to the body, such as influenza and for all diseases directly affecting the respiratory tract such as pneumonia. Additionally, the different mucosal tissues of the human body are interconnected via the so-called “common mucosal immune system”, which allows induction of an antigen-specific immune response in distant mucosal sites. Finally, mucosal administration is also interesting in the area of therapeutic vaccination, in which a predominant cellular immune response is required, as this can efficiently be induced by this route of delivery. The review gives an introduction to respiratory vaccination, formulation approaches and application strategies.

Recent Progress of Supercritical Carbon Dioxide in Producing Natural Nanomaterials

Natural medicines are widely utilized in human healthcare. Their beneficial effects have been attributed to the existence of natural active ingredients (NAI) with a positive impact on disease treatment and prevention. Public awareness about the side effects of synthetic chemical compounds increased the need for NAI as well. Clinical applications of NAI are limited by their instability and poor water solubility, while micronization is a major strategy to overcome these drawbacks. Supercritical carbon dioxide (sc-CO2) based nano techniques have drawn great attention in nanomedicinal area for many years, due to their unique characters such as fast mass transfer, near zero surface tension, effective solvents elimination, non-toxic, non-flammable, low cost and environmentally benign. In terms of functions of sc-CO2, many modified sc-CO2 based techniques are developed to produce NAI nanoparticles with high solubility, biological availability and stability. 5 types of promising methods, including gas-assisted melting atomization, CO2-assisted nebulization with a bubble dryer, supercritical fluidassisted atomization with a hydrodynamic cavitation mixer, supercritical CO2-based coating method and solution-enhanced dispersion by sc-CO2 process, are summarized in this article followed by a highlight of their fundamental synthesis principles and important medicinal applications.

Future of nanomedicines for treating respiratory diseases

INTRODUCTION

Nanoparticles are under discussion in drug delivery for more than 20 years now, but examples for nanoparticulate formulations in the treatment of respiratory diseases are rare and mostly limited to the administration of sub-micron drug particles (ultrafine particles). However, nanoparticles may also carry specific benefits for respiratory treatment. Are nanoparticles the next-generation drug carrier system to facilitate systemic delivery, sustained release and cancer treatment in the lungs?

AREAS COVERED

This review will look into the promises and opportunities of the use of nanoparticles in the treatment of respiratory diseases. Important aspects to discuss are the fate of nanoparticles in the lung and mechanisms for reproducible delivery of nanoparticulate formulations to the lungs. Examples are given where nanoparticles may be advantageous over for traditional formulations and further aspects to explore are mentioned.

EXPERT OPINION

The benefit of nanoparticulate systems for respiratory delivery adds to the portfolio of possible formulation strategies, depends on the intended functionality and needs more exploration. Advantages of such systems are only seen in special cases.

Pharmacological and toxicological assessment of innovative self-assembled polymeric micelles as powders for insulin pulmonary delivery

Aim: Explore the use of polymeric micelles in the development of powders intended for pulmonary delivery of biopharmaceuticals, using insulin as a model protein. Materials & methods: Formulations were assessed in vitro for aerosolization properties and in vivo for efficacy and safety using a streptozotocin-induced diabetic rat model. Results: Powders presented good aerosolization properties like fine particle fraction superior to 40% and a mass median aerodynamic diameter inferior of 6 μm. Endotracheally instilled powders have shown a faster onset of action than subcutaneous administration of insulin at a dose of 10 IU/kg, with pharmacological availabilities up to 32.5% of those achieved by subcutaneous route. Additionally, micelles improved the hypoglycemic effect of insulin. Bronchoalveolar lavage screening for toxicity markers (e.g., lactate dehydrogenase, cytokines) revealed no signs of lung inflammation and cytotoxicity 14 days postadministration. Conclusion: Developed powders showed promising safety and efficacy characteristics for the systemic delivery of insulin by pulmonary administration.

Measles vaccination using a microneedle patch

Measles vaccination programs would benefit from delivery methods that decrease cost, simplify logistics, and increase safety. Conventional subcutaneous injection is limited by the need for skilled healthcare professionals to reconstitute and administer injections, and by the need for safe needle handling and disposal to reduce the risk of disease transmission through needle re-use and needlestick injury. Microneedles are micron-scale, solid needles coated with a dry formulation of vaccine that dissolves in the skin within minutes after patch application. By avoiding the use of hypodermic needles, vaccination using a microneedle patch could be carried out by minimally trained personnel with reduced risk of blood-borne disease transmission. The goal of this study was to evaluate measles vaccination using a microneedle patch to address some of the limitations of subcutaneous injection. Viability of vaccine virus dried onto a microneedle patch was stabilized by incorporation of the sugar, trehalose, and loss of viral titer was less than 1 log10(TCID50) after storage for at least 30 days at room temperature. Microneedle patches were then used to immunize cotton rats with the Edmonston-Zagreb measles vaccine strain. Vaccination using microneedles at doses equaling the standard human dose or one-fifth the human dose generated neutralizing antibody levels equivalent to those of a subcutaneous immunization at the same dose. These results show that measles vaccine can be stabilized on microneedles and that vaccine efficiently reconstitutes in vivo to generate a neutralizing antibody response equivalent to that generated by subcutaneous injection.

Pharmaceutical spray drying: solid-dose process technology platform for the 21st century

Requirement for precise control of solid-dosage particle properties created with a scalable process technology are continuing to expand in the pharmaceutical industry. Alternate methods of drug delivery, limited active drug substance solubility and the need to improve drug product stability under room-temperature conditions are some of the pharmaceutical applications that can benefit from spray-drying technology. Used widely for decades in other industries with production rates up to several tons per hour, pharmaceutical uses for spray drying are expanding beyond excipient production and solvent removal from crystalline material. Creation of active pharmaceutical-ingredient particles with combinations of unique target properties are now more common. This review of spray-drying technology fundamentals provides a brief perspective on the internal process ‘mechanics’, which combine with both the liquid and solid properties of a formulation to enable high-throughput, continuous manufacturing of precision powder properties.

Towards tailored vaccine delivery: needs, challenges and perspectives

The ideal vaccine is a simple and stable formulation which can be conveniently administered and provides life-long immunity against a given pathogen. The development of such a vaccine, which should trigger broad and strong B-cell and T-cell responses against antigens of the pathogen in question, is highly dependent on tailored vaccine delivery approaches. This review addresses vaccine delivery in its broadest scope. We discuss the needs and challenges in the area of vaccine delivery, including restrictions posed by specific target populations, potentials of dedicated stable formulations and devices, and the use of adjuvants. Moreover, we address the current status and perspectives of vaccine delivery via several routes of administration, including non- or minimally invasive routes. Finally we suggest possible directions for future vaccine delivery research and development.

Delivery of antigens used for vaccination: recent advances and challenges

Pasteur’s principle ‘isolate, inactivate, inject’ was the starting point for the successful development of many vaccines, but now, new ways for antigen discovery and vaccine administration present a challenge. Whereas vaccines against polio, measles and influenza are common for many parts of the world, the development of thermostable vaccines not being injected would ease vaccine distribution in developing countries. This review summarizes the general principles of vaccination and looks at common and novel vaccination targets. It also gives a rationale for using other routes than parenteral administration, such as mucosal or transdermal vaccination, and focuses on novel vaccination vehicles, as well as their formulation and stability aspects. Additionally, the review looks at novel application devices for the administration of vaccines.