Intradermal immunization using coated microneedles containing an immunoadjuvant.

A vast number of studies explore the potential of intradermal immunization, its role in the developing of new and improved vaccines and providing access to them globally. The advancement of microneedle technology offers new avenues for the practical realization of this approach, but, on certain instances, introduces new limitations and challenges in the formulation development, which involve the concern over its compatibility with existing and emerging immunoadjuvants. The present paper attempts to review various aspects of immunoadjuvant enhanced microneedle immunization and focuses on the potential of synthetic biomaterials that can play a multifunctional role in such approach. PCPP, a synthetic polyphosphazene macromolecular compound, is discussed as an example of such material that can potentially enable the technology as a microfabrication agent and a potent intradermal immunoadjuvant.