Biodegradable radioactive particles

Abstract

Particles, preferably substantially spherical particles having a smooth outer surface and essentially void-free interior are produced, consisting essentially of solid, cold-water insoluble vehicle comprising a physiologically acceptable, parenterally metabolizable protein or polysaccharide having dispersed therein a water-insoluble carrier loaded with radioisotopes, which are substantially non-leachable upon short term exposure to cold water. Such particles can be administered parenterally for diagnostic purposes, or for treatment with radioactive materials. On administration in this way, they are broken down or solubilized by the body fluids over a predeterminable period ranging from minutes to several days, whereupon the radioisotopic material is excreted from the body thus limiting exposure to the radiation.

What is claimed is: 
     
       1. Tiny free-flowing, unagglomerated radioactive particles of the order of about one-half micron to 1 millimeter in largest dimension, consisting essentially of a gelled vehicle of physiologically acceptable parenterally metabolizable sol-forming polysaccharide of the class consisting of glycogen, starch and dextran or protein of the class consisting of albumin, gelatin and hemoglobin having dispersed therein a physiologically acceptable inorganic carrier for radionuclides, said carrier having solubility product less than about 1×10 -   4 , said carrier containing a radionuclide and being present in said particles in amount ranging from that which is at least adequate to contain said radionuclide up to about 50% by weight based upon the weight of the vehicle, and said particle being resistant to leaching of said radionuclide when immersed in water at 37° C. for at least about 15 minutes. 
     
     
       2. Particles according to claim 1 which are substantially spherular in form. 
     
     
       3. Particles according to claim 1, in which the vehicle is a protein. 
     
     
       4. Particles according to claim 1, in which the vehicle is a polysaccharide. 
     
     
       5. Particles according to claim 1, in which the carrier is a metal salt. 
     
     
       6. Spherules according to claim 2, wherein the vehicle is albumin and the carrier is a metal salt. 
     
     
       7. Spherules according to claim 2, in which the vehicle is a polysaccharide and the carrier is a metal salt. 
     
     
       8. Spherules according to claim 2, in which the vehicle is albumin and the carrier is ferric hydroxide. 
     
     
       9. Spherules according to claim 2, in which the vehicle is albumin, the carrier is sodium iodide and the radionuclide is I 131 . 
     
     
       10. Spherules according to claim 2, in which the vehicle is albumin, the carrier is ferric hydroxide and the radionuclide is cerium 144 . 
     
     
       11. Spherules according to claim 2, in which the vehicle is albumin, the carrier is technetium sulfide and the radionuclide is technetium 99 m . 
     
     
       12. Spherules according to claim 2, in which the vehicle is glycogen and the carrier is ferric hydroxide. 
     
     
       13. Spherules according to claim 2, in which the vehicle is glycogen, the carrier is ferric hydroxide and the radionuclide is cerium 144 . .Iadd. 14. Tiny, free-flowing, unagglomerated particles of the order of about one-half micron to one millimeter in largest dimension adapted for containing radionuclides, consisting essentially of a gelled vehicle of physiologically acceptable parenterally metabolizable sol-forming polysaccharide of the class consisting of glycogen, starch and dextran or protein of the class consisting of albumin, gelatin and hemoglobin having dispersed therein a physiologically acceptable inorganic carrier for radionuclides, said carrier having solubility product less than about 1×10 -   4 , said carrier being present in said particles in amount ranging from that which is at least sufficient to bind radionuclides in the quantity used up to about 50% by weight based upon the weight of the vehicle, and said particles when administered parenterally in the animal organism, being broken down and converted to soluble form. .Iaddend..Iadd. 15. Particles according to claim 14, which are substantially spherical in form. .Iaddend..Iadd. 16. Particles according to claim 15, in narrow size range from about one-half to 60 microns in diameter.