AN EXPERIMENTAL INVESTIGATION OF ENZYME-RELEASE FROM POLY(VINYL ALCOHOL) CROSS-LINKED MICROSPHERES

Crosslinked poly(vinyl alcohol) particles were prepared by the additio n of glutaraldehyde into a PVA methanol/water solution in the presence of 0.2 N sulphuric acid. The polymer solution was dispersed in minera l oil in a jacketed vessel, with the aid of a six-blade impeller. Sphe rical crosslinked particles in the size range 30-80 mu m were obtained by varying the degree of agitation or/and the amount of suspending ag ent. The crosslinked particles, after washing and drying, were placed into a protease enzyme solution for loading. The enzyme-containing wat er-swollen particles were subsequently removed form the solution and t he enzyme release kinetics determined by a UV spectrophotometer. The i nfluence of the degree of crosslinking, ionic strength, pH, particle s ize, and degree of hydrophilicity of the polymer on the enzyme activit y was retained during the adsorption-desorption studies. The release b ehaviour of enzymes from crosslinked PVA particles exhibited a biphasi c kinetic model, with an initial fast release followed by a much slowe r release rate.