125I-Iododeoxyuridine for the Treatment of a Brain Tumor Model:Selection of Conditions for Optimal Effectiveness

The intent of this study was to optimise conditions for the use of 125 IUdR in the treatment of cancer. The radiopharmaceutical plus a biomodulator, methotrexate (MTX) was delivered by intra-tumoral injection of a thermosensitive hydrogel forming a slow release depot of 125 IUdR and MTX in the tumor. Methods: The C6 rat glioblastoma was implanted intra-cranially. A chitosan polymer was used to formulate a biodegradable and biocompatible implant for controlled intra-tumoral delivery of 125 IUdR plus MTX. Results: Intratumoral implant of hydrogel loaded with 7.0 -7.4 MBq of 125 IUdR resulted in survival of 20% of treated animals to 180 days after tumor implant. Simultaneous delivery of MTX increased the number of rats that were effectively cured, to 40%. Conclusion: Using an injectable thermolabile hydrogel as vehicle for 125 IUdR delivery a higher level of tumor control was achieved in a rat glioma model than had been previously reported.