Supercritical processing of PCL and PCL-PEG blends to produce improved PCL-based porous scaffolds

Polycaprolactone (PCL)-based aerogels were prepared by supercritical CO2 drying, with the aim of realizing scaffolds with an open and interconnected structure. PCL only based scaffolds showed a macroporous, irregular section and closed surfaces. Therefore, polyethylene glycol (PEG) was added as a plasticizer, to improve scaffolds morphology. Upon PEG addition, a more regular porous structure of the scaffolds was obtained and PCL+PEG scaffold surfaces were characterized by an open microporosity, attributed to foaming contribution of PEG. Release tests of theophylline demonstrated that most of the unprocessed drug was dissolved in the first 8 min; whereas, its complete release was obtained after 90 min. On the contrary, PCL+PEG scaffolds prolonged the drug release up to 100 times. Drug release curves were fitted using Korsmeyer-Peppas equation, in which n values lower than 0.45 showed that polymer erosion and drug diffusion into the polymeric matrix were the controlling mechanisms of the drug release.