Development of Alginate/Chitosan Microparticles for Dust Mite Allergen

Purpose: To develop chitosan/alginate microparticles for the mucosal delivery of allergen from dust mite (Dermatophagoides pteronyssinus). Methods: Chitosan/alginate microparticles were prepared by ionotropic gelation. The effects of polymer content, crosslinking agent, and preparation method on the physicochemical characteristics of the microparticles as well as their in vitro cytotoxicity were investigated. Results: The microparticles were small (1 - 17 mu m) and spherical in shape. The highest allergen content (0.30 +/- 0.07 mg/g) was obtained with 2.5 % initial allergen loading in chitosan-triphosphate (CS-TPP) microparticles. Sustained allergen release (approx. 50 % over 24 h) was observed from alginate-coated chitosan microparticles. Allergen incorporation method and initial drug-loading could be varied to obtain optimum particle size with high allergen-loading and sustained release. The cytotoxicity of various microparticle formulations did not differ significantly (p > 0.05), as cell viability values were close to 100 %. Conclusion: This study indicates that alginate and alginate-coated chitosan microparticles are safe and can be further developed for mucosal allergen delivery.