Controlled Release Microspheres

Evaluating Internal Microstructures of an Extended Release Microsphere Depot

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.

DigiM FIB-SEM image of a controlled release PLGA microsphere with microporosity — FIB-SEM cross section images used to quantify the internal microstructures of PLGA microspheres. Microporosity and pore size distributions as well as the drug particle size and drug distribution were quantified in 3D using ***DigiM’s AI analytics***.

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.