Composite Hydrogel Embedded with Porous Microspheres for Long-Term pH-Sensitive Drug Delivery

Current delivery of chemotherapy drugs to osteosarcoma is limited by the difficulties in overcoming the solid tumor microenvironment and the cardiotoxicity of doxorubicin (DOX). In previous work we found that phase separation could generate microspheres with high porosity. In this study, we applied these phase-separated porous microspheres as carriers for long-term anticancer drug delivery. Novel poly(propylene fumarate)-co-poly(l-lactic acid) microspheres incorporating DOX were fabricated by thermally induced phase separation. Following embedding into oligo(poly[ethylene glycol] fumarate) hydrogel, the composite system showed prolonged and pH-responsive release of DOX. In vitro cytotoxicity study using osteosarcoma 143B cells showed substantial long-term cytotoxic effects for up to 30 days. As a result, the DOX drug delivery hydrogel developed in this work may have significant potential as a long-term and localized chemotherapy device that would be sensitive to the acidic microenvironment of osteosarcoma and other cancers.