Pulsed controlled-released system for potential use in vaccine delivery

Area of Science:

• Biomaterials Science
• Vaccine Delivery Systems
• Controlled Release Technology

Background:

• Conventional polymeric systems face challenges with water-mediated antigen inactivation.
• Developing stable, single-dose vaccination devices requires protecting antigens from environmental exposure.

Purpose of the Study:

• To engineer biodegradable microcapsules for controlled, single-dose vaccine delivery.
• To protect antigens within an inert microenvironment using microencapsulation.
• To achieve programmed release of antigens at specific time points.

Main Methods:

• Developed core-wall microcapsule structures using poly(D,L-lactide-co-glycolide).
• Entrapped tetanus toxoid (TT) in oil-based cores surrounded by polymer shells.
• Optimized microencapsulation for antigen protection and controlled release profiles.
• Conducted in vitro release studies to validate TT release at 3 and 7 weeks.

Main Results:

• Microcapsules successfully protected tetanus toxoid (TT) within an insulated core.
• Programmed release of immunochemically detected TT was achieved at predetermined times (3 and 7 weeks).
• Over 92% of released TT was immunochemically detected over a 63-day period.
• Formulations demonstrated controlled morphology, structure, and size distribution.

Conclusions:

• Biodegradable microcapsules offer a viable route for single-dose vaccination by preventing antigen inactivation.
• The developed systems provide controlled manner and timing of antigen delivery.
• This technology has the potential to improve vaccine stability and patient compliance.