Assessment of dynamic image analysis as a surrogate dissolution test for a coated multiparticulate product.

Dynamic image analysis (DIA) was used to measure particle diameter (D50) of in-process samples removed during fluid bed coating. A single, rapid measurement gave D50 to within 4 mu m. Samples removed at intervals of 2% weight gain were readily distinguishable by DIA and by their drug release profiles. Drug release was related to D50. DIA was assessed as a surrogate dissolution test with considerable potential. Current limitations of the approach were presented.