Micronizing radiosensitive microcapsules by adding carbonated water to their core material

We have been developing microcapsules that release anticancer drugs in response to radiation with an aim of targeted delivery and increasing the efficacy of anticancer drugs by a combination of these drugs with radiation. The aim of this study was to micronize microcapsules by adding carbonated water to the core material of microcapsules, which releases the anticancer drugs in response to radiation. The core material of microcapsules was prepared by mixing 0.1 g of hyaluronic acid and 0.2 g of alginate into 5 mL of carbonated water. The mixture was sprayed onto a 0.3 mmoL/L solution of calcium chloride (CaCl₂) and ferrous chloride (FeCl₂) using an ultrasound disintegrator. The vibration of the ultrasound disintegrator generated microbubbles in the carbonated water, which micronized the microcapsules. Intravenous injection of the micronized microcapsules to tumor-bearing mice showed that the micronized microcapsules passed more efficiently through the capillaries of lungs or kidneys, which resulted in increased delivery of microcapsules to the tumors and increased the anticancer effect.