Characterizing polymeric drug delivery systems is a challenge due to the decreasing size of delivery vehicles and increasing microstructure complexity. A transport-controlling microporosity system often has pore throats as small as a few tens of nanometers—making it difficult to analyze. In this study conducted with OraPharma, a controlled release delivery system with monolithic poly(lactic-co-glycolic acid) PLGA microspheres, ranging from 30-80 micrometers, was investigated with FIB-SEM imaging and image-based analytics. The release profile of this controlled release delivery system was predicted through an image-based numerical simulation method. 

This characterization approach provides a unique avenue to evaluate the microstructures and structural arrangement of controlled release microparticles and polymeric drug delivery systems. With image-based simulation, optimal formulations and release performance parameters can be fully evaluated.