Mucoadhesive wafers composed of binary polymer blends for sublingual delivery and preservation of protein vaccines

Understanding Mucosal Physiology and Rationale of Formulation Design for Improved Mucosal Immunity

The oral and nasal cavities serve as critical gateways for infectious pathogens, with microorganisms primarily gaining entry through these routes. Our first line of defense against these invaders is the mucosal membrane, a protective barrier that shields the body's internal systems from infection while also contributing to vital functions like air and nutrient intake. One of the key features of this mucosal barrier is its ability to protect the physiological system from pathogens. Additionally, mucosal tolerance plays a crucial role in maintaining homeostasis by regulating the pH and water balance within the body. Recognizing the importance of the mucosal barrier, researchers have developed various mucosal formulations to enhance the immune response. Mucosal vaccines, for example, deliver antigens directly to mucosal tissues, triggering local immune stimulation and ultimately inducing systemic immunity. Studies have shown that lipid-based formulations such as liposomes and virosomes can effectively elicit both local and systemic immune responses. Furthermore, mucoadhesive polymeric particles, with their prolonged delivery to target sites, have demonstrated an enhanced immune response. This Review delves into the critical role of material selection and delivery approaches in optimizing mucosal immunity.

Infant friendly adhesive film containing glucose for neonatal hypoglycemia

Neonatal hypoglycemia is a common disease in newborns, which can precipitate energy shortage and follow by irreversible brain and neurological injury. Herein, we present a novel approach for treating neonatal hypoglycemia involving an adhesive polyvinylpyrrolidone/gallic acid (PVP/GA) film loading glucose. The PVP/GA film with loose cross-linking can be obtained by mixing their ethanol solution and drying complex. When depositing this soft film onto wet tissue, it can absorb interfacial water to form a hydrogel with a rough surface, which facilitates tight contact between the hydrogel and tissue. Meanwhile, the functional groups in the hydrogels and tissues establish both covalent and non-covalent bonds, leading to robust bioadhesion. Moreover, the adhered PVP/GA hydrogel can be detached without damaging tissue as needed. Furthermore, the PVP/GA films exhibit excellent antibacterial properties and biocompatibility. Notably, these films effectively load glucose and deliver it to the sublingual tissue of newborn rabbits, showcasing a compelling therapeutic effect against neonatal hypoglycemia. The strengths of the PVP/GA film encompass excellent wet adhesion in the wet and highly dynamic environment of the oral cavity, on-demand detachment, antibacterial efficacy, biocompatibility, and straightforward preparation. Consequently, this innovative film holds promise for diverse biomedical applications, including but not limited to wearable devices, sealants, and drug delivery systems.

Can the Revolution in mRNA-Based Vaccine Technologies Solve the Intractable Health Issues of Current Ruminant Production Systems?

To achieve the World Health Organization's global Sustainable Development Goals, increased production of high-quality protein for human consumption is required while minimizing, ideally reducing, environmental impacts. One way to achieve these goals is to address losses within current livestock production systems. Infectious diseases are key limiters of edible protein production, affecting both quantity and quality. In addition, some of these diseases are zoonotic threats and potential contributors to the emergence of antimicrobial resistance. Vaccination has proven to be highly successful in controlling and even eliminating several livestock diseases of economic importance. However, many livestock diseases, both existing and emerging, have proven to be recalcitrant targets for conventional vaccination technologies. The threat posed by the COVID-19 pandemic resulted in unprecedented global investment in vaccine technologies to accelerate the development of safe and efficacious vaccines. While several vaccination platforms emerged as front runners to meet this challenge, the clear winner is mRNA-based vaccination. The challenge now is for livestock industries and relevant stakeholders to harness these rapid advances in vaccination to address key diseases affecting livestock production. This review examines the key features of mRNA vaccines, as this technology has the potential to control infectious diseases of importance to livestock production that have proven otherwise difficult to control using conventional approaches. This review focuses on the challenging diseases of ruminants due to their importance in global protein production. Overall, the current literature suggests that, while mRNA vaccines have the potential to address challenges in veterinary medicine, further developments are likely to be required for this promise to be realized for ruminant and other livestock species.

Pediatric and Geriatric-Friendly Buccal Foams: Enhancing Omeprazole Delivery for Patients Encountering Swallowing Difficulties

Buccal foams containing omeprazole (OME) have been developed as potential drug delivery systems for individuals encountering swallowing difficulties, particularly pediatric and geriatric patients. The buccal foams were formulated from lyophilized aqueous gels of maltodextrin, used as a sweetener, combined with various polymers (alginate, chitosan, gelatin, tragacanth) to fine tune their structural, mechanical, and physicochemical properties. Consistent with the requirements for efficient drug delivery across buccal epithelium, the foam comprised of hydroxypropyl methylcellulose and alginate (HPMC-Alg-OME), exhibited moderate hardness and high mucoadhesion resulting to prolonged residence and increased transport of the active across porcine epithelium. The HPMC-Alg-OME foam induced a 30-fold increase in the drug's apparent permeability across porcine buccal tissue, compared to the drug suspension. The developed buccal foams exhibited excellent stability, as evidenced by the unchanged omeprazole content even after six months of storage under ambient conditions (20 °C and 45% RH). Results indicate that buccal foams of omeprazole may address the stability and ease of administration issues related to oral administration of the drug, particularly for children and elderly patients who have difficulty swallowing solid dosage forms.

Mucoadhesive Vaccine Delivery Systems for the Oral Mucosa

Vaccine technology has evolved continuously since its beginning, and mucosal vaccination, including intranasal, sublingual, and oral administrations, has recently gained great scientific interest. The oral mucosa represents a promising minimally invasive route for antigen delivery, mainly at sublingual and buccal mucosal sites, and it is easily accessible, immunologically rich, and able to promote an effective systemic and local immune response. The aim of this review is to provide an updated overview on the technologies for oral mucosal vaccination, with emphasis on mucoadhesive biomaterial-based delivery systems. Polymeric-based nanoparticles, multilayer films and wafers, liposomes, microneedles, and thermoresponsive gels are the most investigated strategies to deliver antigens locally, showing mucoadhesive properties, controlled release of the antigen, and the ability to enhance immunological responses. These formulations have achieved adequate properties in terms of vaccine stability, are minimally invasive, and are easy to produce and manage. To date, oral mucosa vaccine delivery systems represent a promising and open field of research. Future directions should focus on the role of these systems to induce sustained innate and adaptive immune responses, by integrating the recent advances achieved in mucoadhesion with those related to vaccine technology. Being painless, easy to administer, highly stable, safe, and effective, the antigen delivery systems via the oral mucosa may represent a useful and promising strategy for fast mass vaccination, especially during pandemic outbreaks.

The Role of Mucoadhesion and Mucopenetration in the Immune Response Induced by Polymer-Based Mucosal Adjuvants

Mucus is a viscoelastic gel that acts as a protective barrier for epithelial surfaces. The mucosal vehicles and adjuvants need to pass through the mucus layer to make drugs and vaccine delivery by mucosal routes possible. The mucoadhesion of polymer particle adjuvants significantly increases the contact time between vaccine formulations and the mucosa; then, the particles can penetrate the mucus layer and epithelium to reach mucosa-associated lymphoid tissues. This review presents the key findings that have aided in understanding mucoadhesion and mucopenetration while exploring the influence of physicochemical characteristics on mucus-polymer interactions. We describe polymer-based particles designed with mucoadhesive or mucopenetrating properties and discuss the impact of mucoadhesive polymers on local and systemic immune responses after mucosal immunization. In future research, more attention paid to the design and development of mucosal adjuvants could lead to more effective vaccines.

Expanding opportunities to engineer mucosal vaccination with biomaterials

Mucosal vaccines are receiving increasing interest both for protecting against infectious diseases and for inducing therapeutic immune responses to treat non-infectious diseases. However, the mucosal barriers of the lungs, gastrointestinal tract, genitourinary tract, nasal, and oral tissues each present unique challenges for constructing efficacious vaccines. Vaccination through each of these mucosae requires transport through the mucus and across specialized epithelia to reach tissue-specific immune cells and lymphoid structures, necessitating finely tuned and multifunctional strategies. Serving as inspiration for mucosal vaccine design, pathogens have evolved elaborate, diverse, and multipronged approaches to penetrate and infect mucosae. This review is focused on biomaterials-based strategies, many inspired by pathogens, for designing mucosal vaccine platforms. Passive and active technologies are discussed, along with the microbial processes that they seek to mimic.

Alginate as a Promising Biopolymer in Drug Delivery and Wound Healing: A Review of the State-of-the-Art

Biopolymeric nanoparticulate systems hold favorable carrier properties for active delivery. The enhancement in the research interest in alginate formulations in biomedical and pharmaceutical research, owing to its biodegradable, biocompatible, and bioadhesive characteristics, reiterates its future use as an efficient drug delivery matrix. Alginates, obtained from natural sources, are the colloidal polysaccharide group, which are water-soluble, non-toxic, and non-irritant. These are linear copolymeric blocks of α-(1→4)-linked l-guluronic acid (G) and β-(1→4)-linked d-mannuronic acid (M) residues. Owing to the monosaccharide sequencing and the enzymatically governed reactions, alginates are well-known as an essential bio-polymer group for multifarious biomedical implementations. Additionally, alginate’s bio-adhesive property makes it significant in the pharmaceutical industry. Alginate has shown immense potential in wound healing and drug delivery applications to date because its gel-forming ability maintains the structural resemblance to the extracellular matrices in tissues and can be altered to perform numerous crucial functions. The initial section of this review will deliver a perception of the extraction source and alginate’s remarkable properties. Furthermore, we have aspired to discuss the current literature on alginate utilization as a biopolymeric carrier for drug delivery through numerous administration routes. Finally, the latest investigations on alginate composite utilization in wound healing are addressed.

Mucosal vaccine delivery: A focus on the breakthrough of specific barriers

Mucosal vaccines can effectively induce an immune response at the mucosal site and form the first line of defense against microbial invasion. The induced mucosal immunity includes the proliferation of effector T cells and the production of IgG and IgA antibodies, thereby effectively blocking microbial infection and transmission. However, after a long period of development, the transformation of mucosal vaccines into clinical use is still relatively slow. To date, fewer than ten mucosal vaccines have been approved. Only seven mucosal vaccines against coronavirus disease 2019 (COVID-19) are under investigation in clinical trials. A representative vaccine is the adenovirus type-5 vectored COVID-19 vaccine (Ad5-nCoV) developed by Chen and coworkers, which is currently in phase III clinical trials. The reason for the limited progress of mucosal vaccines may be the complicated mucosal barriers. Therefore, this review summarizes the characteristics of mucosal barriers and highlights strategies to overcome these barriers for effective mucosal vaccine delivery.