Effect of the Coating Morphology on the Drug Release from Engineered Drug-Polymer Nanocomposites

The ElectroNanospray (TM) process (Nanocopoeia, Inc) transforms drugs and polymers into many nanoscale material states including powders, liquids, encapsulated particles, and coatings. This enabling technology platform allows application of polymers and drugs to the surface of medical devices such as coronary stents in a single-stage process. Modification of ElectroNanospray process parameters resulted in surface coatings with rich morphologies ranging in appearance from smooth and heterogeneous to highly porous and rough (open matrix). The traditional approach of measuring percent release over time by HPLC shows that the drug release profiles change significantly with coating morphology. In this study, we employed high resolution imaging techniques such as SEM, Atomic Force Microscopy (AFM) and Confocal Raman Microscopy to elucidate the drug release process on these coatings in situ, indicating a correlation of release kinetics with coating morphology.