Effects of Al³⁺ Ion on Tc-99m Sulfur Colloid Preparations with Different Buffers

Abstract

The effect of aluminum ions on two Tc-99m sulfur colloid preparations, one with phosphate buffer and the other with acetate buffer, was studied by the filtration technique using Nuclepore filters of sizes 0.6 μm, 3 μm, and 10 μm. The aluminum concentrations were < 0.5, 7.5, and 15 μg/ml of the final preparation. A considerable number of large particles (3-10 μm) formed in the sulfur colloid preparation containing phosphate buffer when the Al³⁺ concentration was 7.5 μg/ml or more. This particle formation was not observed with sulfur colloid preparation containing acetate buffer.