Biodegradable radiation delivery system utilizing glass microspheres and ethylenediaminetetraacetate chelation therapy

Dysprosium lithium‐borate (DyLB) glass microspheres have been developed as a biodegradable radiation delivery vehicle for the treatment of rheumatoid arthritis and other diseases. Radioactive microspheres of these glasses are intended to be injected into a joint infected with rheumatoid arthritis to safely deliver a localized dose (100 Gy) of beta radiation. Once injected, the microspheres react nonuniformly with body fluids. The nonradioactive, lithium‐borate component is dissolved from the glass, whereas the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes “chemically” trapped in a solid, dysprosium phosphate reaction product that has the same size as the unreacted microsphere. The glass microspheres lose ≈80% of their weight after nonuniform reaction (