Local delivery of polymeric 125I-IUdR to experimental human malignant gliomas

Ma Xiaodong; Larry E.Dillehay; Jerry R.Williams; Jeffery A.Williams

doi:10.3969/j.issn.1671-2897.2005.04.002

Abstract：Objective To detect the role of implantable biodegradable polymers for the local delivery of 125I radiolabeled idoxuridine (IUdR).Methods Para-carboxyphenoxypropane: sebacic acid (PCPP:SA) polymers (10 mg, 25 μCi of the 125I-IUdR) and polyphosphoester (PPE) polymers (15 μg:25 μCi) were synthesized and the release of the radioactivity was counted by a calibrated scintillation counter both in vitro and in vivo. Results PCPP:SA resulted in controlled, protracted release of 125I-IUdR vs. time in vitro, and the similar outcomes were obtained in vivo. The counting of the blood after implantation of the flank PCPP:SA polymers showed the release was much faster than for the intracranial (IC) polymer. For the counting of flank tumors after ipsilateralral (IP) vs. contralateral (CL) polyphosphoester (PPE) 125I-IUdR injection, the release speed of both sides were similar, but the IP polymer had a much higher local concentration than for the CL polymer. The release of the PPE 125I-IUdR polymer into the blood was similar in both side implanted polymers. Autoradiographic quantification of the activity section showed decreasing activity vs. distance from the polymeric implant and decreasing activity for CL vs. IP 125I-IUdR polymeric implantation. Organs counts showed that the highest content was for the intestine, followed by the spleen measured 2, 4, and 8 days after the polymers implantation.Conclusion The implantable and biodegradable polymers make radiolabled IUdR more concentrate in the implanted site and protracte its release.