Tumor targeting of HPMA copolymer conjugates containing sulfadiazine groups

To develop new tumor targeting macromolecular conjugates, poly(HPMA)-SD-APMA-DTPA (HPMA: N-(2-hydroxypropyl)-methacrylamide; APMA: N-(3-aminopropyl)methacrylamide; DTPA: diethylenetriaminepentaacetic acid; SD: sulfadiazine) was synthesized and characterized. The poly(HPMA)-SD-DTPA conjugates were radiolabeled with the radionuclide 99mTc and tested for uptake by cultured H22 cells in vitro. DTPA-99mTc (radiotracer 1) and poly(HPMA)-DTPA-99mTc (radiotracer 2) were also synthesized and characterized for comparison. The uptake of poly(HPMA)-SD-DTPA-99mTc (radiotracer 3, 34.76%) was significantly higher than that of poly(HPMA)-DTPA-99mTc (16.40%), indicating that uptake of the poly(HPMA)-SD-DTPA-99mT was active binding. The uptake of poly(HPMA)-DTPA-99mTc was significantly higher than that of DTPA-99mTc (2.98%), suggesting that uptake of the poly(HPMA)-DTPA-99mT was passive binding. The data suggest that the poly(HPMA)-SD-APMA-DTPA conjugates might be useful as tumor targeting macromolecular conjugates.