90Y-labeled tin fluoride colloid as a promising therapeutic agent: Preparation, characterization, and biological study in rats

In this study, tin fluoride colloid (SnF-c) was prepared, labeled with yttrium-90 (90Y), and characterized with respect to its physicochemical properties and biological behavior in an animal model. Particle size of SnF-c, at constant concentration of SnF2, was dependent on pH, concentration of sodium fluoride (NaF), temperature, and time. The particle size of SnF-c decreased with an increase in NaF concentration and a decrease in reaction mixture pH. Radiolabeling yield of 90YSnF-c at higher temperature increased and it was greater than 98% for the preparation at 95 degrees C. The 90YSnF-c demonstrated high in vitro stability both in human serum and human synovial fluid at 37 degrees C up to 7 days. In vivo distribution studies in healthy male Wistar rats of 90YSnF-c (particles <1 mu m), following intravenous administration, revealed that the localization takes place preferably in the liver. The 90YSnF-c (particles >1 mu m) was well retained in the synovial space for 96 h after intra-articular injection, whereas leakage of 90Y from the joint was 1.96% over this period. Because of high labeling yield and stability, 90YSnF-c might be a promising agent for radiosynovectomy or therapy of liver malignancies. (C) 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 101:21942203, 2012