188Rhenium(V)-dimercaptosuccinic acid loaded poly(lactic-co-glycolic)acid microspheres for targeted radiotherapy: production and effectivity.

Poly(lactic-co glycolic)acid (75:25) (PLGA) microspheres for the delivery of a radiation dose to tumors were synthesized after loading the 188Re(V) labeled DMSA. The 188ReO4- in place of 99mTcO4- was replaced to label DMSA, because of their structural and chemical similarities and to make the molecule site specific for radiotherapy. The radiolabeling efficiency of DMSA was more than 97% as confirmed by ITLC. A solvent evaporation technique was used to encapsulate DMSA in PLGA microspheres. Electron microscopy demonstrated the microspheres size ranged between 0.4-1.8 microm. As demonstrated by DSC, DMSA was encapsulated (20-30%) within the microspheres in solid solution, metastable molecular dispersion or crystallization forms. In vitro release studies confirmed the stability of DMSA.