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

Abstract

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.

Chitosan and Anionic Solubility Enhancer Sulfobutylether-β-Cyclodextrin-Based Nanoparticles as Dexamethasone Ophthalmic Delivery System for Anti-Inflammatory Therapy

“…However, it is worth considering that smaller-sized NPs provide a larger specific surface area for interaction with the mucin layer, significantly enhancing the mucoadhesive properties of the formulation [ 65 ]. Moreover, smaller-sized NPs facilitate mucopermeation through mucosal barriers, ensuring drug release into the underlying tissues [ 66 ]. The low molecular weight CS NPs particularly exhibited a low PDI value, ensuring the homogeneous dispersion of NPs.…”

“…In fact, the enhanced retention of nanoparticles on the ocular surface due to nanoparticle size may be responsible for the increased penetration from the nanoparticles as compared to the control (marketed formulation) [ 23 , 74 ]. Furthermore, the presence of CS in the produced NPs may have contributed to enhancing the mucopenetration of the DEX-loaded NPs by opening mucin meshwork, facilitating the release of DEX into the underlying lipophilic layer [ 66 ]. As a result of this behavior, DEX-loaded NPs could be strongly recommended in the post-operative treatment of cataracts and, specifically, in the treatment of inflammatory states in older subjects.…”

Muco-Adhesive and Muco-Penetrative Formulations for the Oral Delivery of Insulin

“…Greater surface density of targeting ligands such as lectins, invasins, and vitamin B12, along with permeation enhancers such as mucolytic drugs, promote diffusivity through the mucus layer, enabling access to the cells in the Peyer’s patch. The attachment of any ligand allows specific binding with M cells or mucosal epithelial cells . Often, the particles work through a viscous fingering phenomenon wherein lower viscosity fluid entering a higher viscosity fluid creates pressure-driven channels of low viscosity fluid that drive osmotically driven absorption and consequent absorption-driven endocytic entry into the enterocytes …”

“…Nanoformulations, targeting improved oral insulin bioavailability, aim either to extend residence time within the mucus (muco-adhesive formulations) or to penetrate the mucus barrier and access circulation (muco-penetrative formulations). There are several reports on the utilization of MA and MP formulations for the enhanced drug uptake/release, which are mainly due to various intermolecular forces (including van der Waals, hydrogen bonding, and electrostatic interactions) 19 established between the formulations and mucin proteoglycans. Figure 4 highlights some key differences in the characteristics between these two types of formulations.…”

The Use of Particulate Systems for Tuberculosis Prophylaxis and Treatment: Opportunities and Challenges

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