Production and quality control of 166Ho-Chitosan for therapeutic applications

Introduction: In this research, [166Ho]Holmium chitosan complex production is described in details, followed by determination of complex radiochemical purity, stability and biodistribution (after intra-articular injection) in wild-type male rats. Finally a Ho-166 based chitosan kit for ultimate radiosynovectomy as well as radiotherapy applications was developed. Methods: 166Ho-chitosan complex was prepared using chitosan concentrations and 166HoCl3 followed by intra-articular injection and biodistribution studies in wild-type rats including and excluding injected knee. Results: The [166Ho]Holmium chitosan complex was prepared with high radiochemical yield (>95 %) in the optimized condition (35mg/3ml of chitosan  in %1 AcOH, pH. 3, >98%, ITLC) was injected to wild-type rats followed by the biodistribution studies of the compound among the tissues excluding the injected knee data. Intra-articular injection of [166Ho]holmium chitosan complex to male wild-type rats and investigation of leakage of activity in  the body showed that most of injected dose has remained in injection site 144 h after injection. Conclusion: Successful development and formulation of 166Ho-chitosan kit is described. This kit has the potential for use in clinical setting namely for radiosynovectomy and cancer radiochemotherapy.