Vaccine and Pharmaceutical Formulation and Stabilization Technologies

Mucosal immunization

Novel technologies for improved protection

AIDS, tuberculosis, acute respiratory-tract infections, and diarrheal diseases account for millions of deaths annually worldwide. All are caused by pathogens that enter the body via the mucosa—tissue linings found in the oral cavity as well as the reproductive, respiratory, and gastrointestinal tracts.

Vaccines administered directly to the mucosa can trigger key antibodies and preferentially activate specific cells. Yet, mucosal vaccines face significant barriers to success due to in situ dilution and dispersion, interference from inert food and dust particles, enzymatic degradation, and low pH in the stomach. These and other factors can limit the ability of the vaccine to reach its target immune cells, resulting in a suboptimal immune response. To more effectively protect people from pathogens that enter the body via the mucosa, new technological approaches are needed to achieve mucosal immunization.

An enabling innovation

PATH is developing a mucosal immunization technology platform that builds on several proven formulation, adjuvant, and delivery technologies to enable the efficient sublingual (under the tongue) administration of subunit and other vaccines.

The technology platform is viable in two product formats:

  • Thermoresponsive gel. This format begins as a liquid solution at room temperature and transforms into a gel upon contact with the oral mucosa. Its gel matrix enables it to adhere to mucosal surfaces and protects the vaccine antigen from degradation caused by salivary enzymes. Visit our page on the thermoresponsive gel to learn more »
  • Fast-dissolving tablet. This freeze-dried product format disintegrates instantly in a small amount of saliva. It can also be reconstituted in diluents or a buffer and then administered orally with a liquid dropper. Visit our page on the fast-dissolving tablet to learn more »

Both formats contain a thermoresponsive polymer, a penetration enhancer, a muco-adhesive agent, and a safe and potent adjuvant.

  • The polymer serves as a phase-transition agent, facilitating the change from a liquid to a gel. In the case of the tablet formulation, it functions as a binder.
  • The penetration enhancer creates an opening for large antigen molecules to enter the mucosa through the otherwise tight junctions of the mucosal epithelial cells.
  • The muco-adhesive agent helps to retain both formats at the application site for 20 minutes or longer. High retention maximizes the proportion of the administered antigen that gains access to the dendritic cells (the specialized antigen-presenting cells that initiate immune responses).
  • The adjuvant helps to augment both mucosal and systemic immune responses. Visit our page on enhancing product efficacy to learn more about our work with adjuvants »

Additional assessments are underway as PATH continues to research these two formats as value-added product presentations for human and veterinary vaccines, and certain medications.

Additional information

 

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