Vaccine Drug Delivery Systems

Vaccines are the pharmaceutical preparations given to patients to induce immune responses leading to the production of antibodies or cell-mediated responses that will combat infectious agents or non-infectious conditions such as cancer cell growth. Checking the safety profile of live vaccines, weak immunogenicity of sub-unit vaccines and immunization, failure due to poor patient compliance to booster doses which should potentiate prime doses are few strong reasons, which necessitated the development of new generation of prophylactic and therapeutic vaccines to promote effective immunization. Efforts are being made to deliver vaccines through carriers as they control the spatial and temporal presentation of antigens to immune system thus leading to their sustained release and targeting. The lower doses of weak immunogens can be successfully directed to stimulate immune responses and eradicate the need for the administration of main and important booster doses as a part of conventional vaccination regimen. This paper reviews carrier systems such as microspheres, liposomes, dendrimers, nanoparticles, ISCOMs, micellar systems, plant-derived viruses which are now being examined and developed as vaccine delivery systems. This paper also defines various aspects of “needle-free technologies” used to manage the vaccine delivery systems through different routes into the human body.