Evaluation of Injectable Chitosan-based Co-cross-linking Hydrogel for Local Delivery of 188 Re-LIPO-DOX to Breast-tumor-bearing Mouse Model.

Background/Aim: An injectable chitosan-based cross-linking thermosensitive hydrogel combining Re-188- and doxorubicin-encapsulated liposomes (C/GP/GE/ Re-188-LIPO-DOX) was developed for the prevention of locoregional recurrence after mastectomy. Materials and Methods: The hydrogel properties, in vitro drug release characteristics, and in vivo scintigraphy imaging attributes were investigated. Results: The gelation time of the hydrogels can be controlled to be within 5 min. Results from Fourier-transform infrared spectroscopy, scanning electron microscopy, and dynamic mechanical analysis showed that a covalent cross-linking reaction between chitosan and genipin occurred and that the hydrogel's mechanical strength and chemical stability were improved. In vitro drug release studies showed that the hydrogel can prolong the release of doxorubicin by several weeks (51.5%+/- 5.3% at 21 days). In addition, in vivo scintigraphy results suggested high retention rates (43.1%11.0% at 48 h) of the radiopharmaceutical compound at the tumor injection site. Conclusion: The preliminary results indicated that the C/GP/GE/ Re-188-LIPO-DOX radiopharmaceutical hydrogel is a potential candidate for further in vivo therapeutic evaluation.