mucosaltargeting

Mucosal targeting refers to strategies designed to deliver therapeutic agents to mucosal surfaces or to exploit the mucosal immune system, with goals including local action, enhanced systemic absorption from mucosal routes, or elicitation of mucosal and systemic immune responses. Common mucosal sites include the nasal, oral, gastrointestinal, pulmonary, vaginal, and ocular tracts.

The mucosal barrier is a dynamic, protective environment composed of a mucus layer, an epithelial cell layer, and an underlying immune network. The mucus layer is a viscoelastic gel rich in mucins, enzymes, and lipids, which can impede diffusion and residence time but also provides opportunities for selective interaction. Effective mucosal targeting requires balancing residence time with the ability of agents to penetrate mucus and reach epithelial or immune cells.

Approaches used to achieve mucosal targeting include: mucoadhesive formulations that adhere to the mucus or epithelium to prolong residence time; mucus-penetrating particles designed to diffuse through mucus without becoming trapped; ligand-based targeting to specific mucosal cells or receptors (for example, M cells in gut-associated lymphoid tissue or dendritic cells); and stimuli-responsive systems that release cargo in response to pH, enzymes, or other local cues. Delivery routes such as intranasal and sublingual administration are commonly pursued for systemic or CNS targeting, while inhalation and oral mucosal routes support local or immune-mediated outcomes.

Evaluation relies on mucus diffusion studies, in vitro cell models, ex vivo tissue tests, and in vivo pharmacokinetic and immunogenicity assessments. Challenges include mucus variability, safety, manufacturing complexity, and regulatory considerations, but mucosal targeting remains an active area of pharmaceutical research with potential across vaccines, peptides, and biologics.