Formulation aspects of biodegradable polymeric microspheres for antigen delivery

Biodegradable microspheres (MS) have proven to be very useful antigen delivery systems that are ingested by immunocompetent cells and provide prolonged antigen release and lasting immunity thanks to sustained release of the microencapsulated material. This review provides an applicable summary of different formulation routes for the purpose of producing safe, qualified and efficacious products of microencapsulated peptide and protein antigens. We have brought to attention, with case examples, not only the most common means of improving the quality of microsphere formulations, i.e., the use of stabilising additives, but also less commonly known and applied approaches, e.g., ion pairing, novel polymer systems, solid-state and other innovative microencapsulation methods.