Magnetically directed poly(lactic acid) [sup 90]Y-microspheres: Novel agents for targeted intracavitary radiotherapy
- Harvard Medical School, Boston, MA (United States). Joint Center for Radiation Therapy
High energy [beta]-emitting radioisotopes like Yttrium-90 have a radiotoxic range of about one centimeter. For cancer treatment they must be brought near the tumor cells and kept there for as long as they are radioactive. The authors developed as carriers for the ionic form of [sup 90]Y a matrix-type polymeric drug delivery system, poly(lactic acid) (PLA) microspheres. This radiopharmaceutical could be selectively delivered to the target site after incorporating 10% Fe[sub 3]O[sub 4] which made the magnetic microspheres (MMS) responsive to an external magnetic field. Furthermore, MMS are biodegradable and slowly hydrolyze into physiologic lactic acid after the radioactivity is completely decayed. Previously prepared 10--40 [mu]m MMS were radiochemically loaded to high specific activity with [sup 90]Y at a pH of 5.7. Stability studies showed that approximately 95% of added [sup 90]Y is retained within the PLA matrix after 28 days (> 10 half-lives) at 37 C in serum, and electron microscopy showed that the microspheres retained their characteristic morphologic appearance for the same time period. Cytotoxicity studies with SK-N-SH neuroblastoma cells growing in monolayer showed that the radiocytotoxicity of the microspheres could be directed magnetically to either kill or spare specific cell populations, thus making them of great interest for targeted intracavitary tumor therapy. The authors are currently optimizing this system for use in the treatment of neoplastic meningitis.
- OSTI ID:
- 6910655
- Journal Information:
- Journal of Biomedical Materials Research; (United States), Vol. 28:8; ISSN 0021-9304
- Country of Publication:
- United States
- Language:
- English
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MICROSPHERES
SPECIFICITY
NEOPLASMS
RADIOIMMUNOTHERAPY
YTTRIUM 90
THERAPEUTIC USES
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
HOURS LIVING RADIOISOTOPES
IMMUNOTHERAPY
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MEDICINE
NUCLEAR MEDICINE
NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
THERAPY
USES
YTTRIUM ISOTOPES
550604* - Medicine- Unsealed Radionuclides in Therapy- (1980-)