Definition

A gel-based formulation composed of a very dilute solution of hydrogen peroxide (H2O2) combined with hyaluronic acid (HA), with potential radiosensitizing activity. Upon intratumoral injection and slow-release (SR) of H2O2 from the gel, H2O2 releases oxygen and inactivates anti-oxidative enzymes, thereby increasing the oxygen concentration in the tumor environment, which increases the efficacy of radiotherapeutic treatment. HA increases viscosity of the formulation and allows for the SR of H2O2; as compared to the injection of H2O2 alone, the addition of HA decreases diffusion of H2O2 to surrounding areas and enhances intratumoral H2O2 concentration over an increased period of time. Hypoxic tumors show a decreased response to radiotherapy; thus, increasing oxygen content increases tumor response to radiotherapy.