BIODEGRADABLE MICROPARTICLES AS A DELIVERY SYSTEM FOR THE ALLERGENS OF DERMATOPHAGOIDES-PTERONYSSINUS (HOUSE-DUST MITE) .1. PREPARATION AND CHARACTERIZATION OF MICROPARTICLES

The encapsulation of allergens into biodegradable microparticles may offer the potential for novel forms of hyposensitization therapy. The use of microparticles for hyposensitization therapy may offer the potential advantages of a reduced number of doses, through controlled release of allergens, and the possibility of oral delivery. Nevertheless, a possible concern is the effect of the microencapsulation process on the integrity and activity of the entrapped allergens. Therefore, in the current studies, an allergen, Dermatophagoides pteronyssinus (D.Pt.), was entrapped in poly(lactide-co-glycolide) (PLG) microparticles and several established techniques were used to investigate the integrity of the entrapped allergen. Isoelectric focusing indicated that all the protein components of the allergen were successfully entrapped in the microparticles. A radioallergosorbent test (RAST) inhibition assay indicated that there was a minor reduction in the binding of specific IgE to the entrapped allergen, but this was thought unlikely to affect the ability of the allergen to act as a hyposensitizing agent. Finally, the IgG binding activity of the major allergenic component of D.Pt. (Der PI) was shown to be unchanged following microencapsulation. Hence, the current studies indicated that the allergen D.Pt., was not adversely affected following encapsulation into PLG microparticles. Therefore, microparticles may have potential as delivery systems for hyposensitization therapy.