Development of a nano-zirconia based ⁶⁸Ge/⁶⁸Ga generator for biomedical applications

Abstract

Introduction: Most of the commercially available ⁶⁸Ge/⁶⁸Ga generator systems are not optimally designed for direct applications in a clinical context. We have developed a nano-zirconia based ⁶⁸Ge/⁶⁸Ga generator system for accessing ⁶⁸Ga amenable for the preparation of radiopharmaceuticals. Methods: Nano-zirconia was synthesized by the in situ reaction of zirconyl chloride with ammonium hydroxide in alkaline medium. The physical characteristics of the material were studied by various analytical techniques. A 740 MBq (20 mCi) ⁶⁸Ge/⁶⁸Ga generator was developed using this sorbent and its performance was evaluated for a period of 1 year. The suitability of ⁶⁸Ga for labeling biomolecules was ascertained by labeling DOTA-TATE with ⁶⁸Ga. Results: The material synthesized was nanocrystalline with average particle size of ∼7 nm, pore-size of ∼4 Å and a high surface area of 340±10 m² g^-1. ⁶⁸Ga could be regularly eluted from this generator in 0.01N HCl medium with an overall radiochemical yield >80% and with high radionuclidic (<10^-5% of ⁶⁸Ge impurity) and chemical purity (<0.1 ppm of Zr, Fe and Mn ions). The compatibility of the product for preparation of ⁶⁸Ga-labeled DOTA-TATE under the optimized reaction conditions was found to be satisfactory in terms of high labeling yields (>99%). The generator gave a consistent performance with respect to the elution yield and purity of ⁶⁸Ga over a period of 1 year. Conclusions: The feasibility of preparing an efficient ⁶⁸Ge/⁶⁸Ga generator which can directly be used for biomedical applications has been demonstrated.