EFFECT OF SUPERDISINTEGRANT ON ANTIGEN RELEASE FROM ENTERIC-COATED ANTIGEN MICROSPHERES

The effect of incorporation of a superdisintegrant into an oral enteri c-coated antigen microsphere (ECAM) delivery system was studied. The m ixture of antigen and sodium starch glycolate (SSG, Explotab(R)) was a pplied onto 25- to 30-mesh nonpareil beads followed by coating with po lymethacrylic acid-ethylacrylate. (PMA-EA, Eudragit(R) L-30D). Lipopol ysaccharide (LPS) was used as a model antigen. The amount of antigen r eleased from the ECAMs in dissolution medium as a function of time was determined by a size-exclusion HPLC method with UV detection. The lev el of superdisintegrants incorporated was optimized by adding differen t amount of SSG onto the beads. Study results indicated 12% (w/w) SSG provided the significantly faster release of LPS than other formulatio ns. The time of the beads with SSG incorporated began to break apart t he enteric film was 1.24, 1.26, 1.34, 1.58 and 1.86 min for 12%, 9%, 5 %, 3%, and 1% superdisintegrant added formulation, respectively. The d isintegrating time of SSG incorporated beads was significantly less th an that of non-SSG incorporated beads (2.97 min, p < 0.05). Beads inco rporated with 9% and 12% SSG always yielded significantly larger swell ing and liquid uptake capacity. The significantly faster antigen relea se rate and the reduced time needed for breaking the Eudragit film may due to the swelling forces generated by incorporation of the superdis integrant in the beads. The 12% (w/w) SSG formulation has the fastest release rate and the shortest film breaking time because 12% SSG micro spheres take up a larger amount of water and provide higher swelling f orces.