Impact of formulation on solid oxygen-entrapping materials to overcome tumor hypoxia

Tumor hypoxia, resulting from rapid tumor growth and aberrant vascular proliferation, exacerbates tumor aggressiveness and resistance to treatments like radiation and chemotherapy. To increase tumor oxygenation, we developed solid oxygen gas-entrapping materials (O₂-GeMs), which were modeled after clinical brachytherapy implants, for direct tumor implantation. The objective of this study was to investigate the impact different formulations of solid O₂-GeMs have on the entrapment and delivery of oxygen. Using a Parr reactor, we fabricated solid O₂-GeMs using carbohydrate-based formulations used in the confectionary industry. In evaluating solid O₂-GeMs manufactured from different sugars, the sucrose-containing formulation exhibited the highest oxygen concentration at 1 mg/g, as well as the fastest dissolution rate. The addition of a surface coating to the solid O₂-GeMs, especially polycaprolactone, effectively prolonged the dissolution of the solid O₂-GeMs. In vivo evaluation confirmed robust insertion and positioning of O₂-GeMs in a malignant peripheral nerve sheath tumor, highlighting potential clinical applications.