Injectable PLGA Systems for Delivery of Vaccine Antigens

Abstract

Micro and nanoparticles prepared from poly (lactic-co-glycolic acid) (PLGA) polymer represent a unique and promising delivery system for vaccine antigens. Administration of PLGA with adsorbed or encapsulated antigens has been shown to improve immunogenic responses in mammals relative to administration of soluble antigen. PLGA microparticles are capable of delivering a number of agents simultaneously and presenting multiple copies of antigens on the polymer surface, both which lead to a stronger activation signal. PLGA microparticles can also trap and retain the antigens in local lymph nodes and protect them from proteolytic degradation, ensuring longer stimulation by the antigen. Since the interior of PLGA microparticles is not a "friendly" environment for most proteins, each protein antigen vaccine requires careful optimization. Over the last 10 years, significant advances in antigen stabilization have been made. It is expected that the first clinical use of this dosage form for vaccines will be for treatment of diseases such as cancer instead of prophylactic immunization in healthy populations. © Controlled Release Society 2012.