Biodegradable Bioadherent Microcapsules for Orally Administered Sustained Release Vaccines. Phase 1.

Traditional vaccines have many characteristics which pose logistical problems for both military and civilian vaccinations programs. Currently, vaccines require several booster injections to obtain maximum protection, they are often effective against only a single organism and most require refrigeration. Biodegradable microspheres for vaccine encapsulation could eliminate many of these problems. Microencapsulated vaccines offer the promise of extended antigen presentation, thus eliminating the need for booster injections. Microencapsulation also allows incorporation of multiple antigens in a single dose. This report describes the production and in vivo evaluation of a new microsphere vaccine approach. Several microsphere tetanus and botulinum vaccine formulations were examined in vivo using a BALB/c mouse model. Several formulations of microencapsulated vaccines provided both an elevated and prolonged serum IgG response. At 9 weeks post injection, the microsphere vaccine evidenced 47% of its initial (2 week) serum IgG levels, without a booster injection. This study has demonstrated that this biodegradable microsphere antigen delivery system has the potential for prolonged protection. The vaccine delivery system described in this report, if successfully developed, will benefit military and civilian health efforts and could be marketed around the world.