Comparison and systematic optimization of synthetic protocols for DOTA–hydrazide generation

DOTA-based organometallic complexes are extensively used in functional and molecular imaging studies, as well as in radioimmunotherapy. DOTA forms thermodynamically stable and kinetically inert complexes with various different diagnostic and therapeutic metals, such as gadolinium, gallium, yttrium and indium. Here, we have compared and systematically optimized the two most commonly used synthetic protocols for generating DOTA–hydrazide complexes, identifying conditions which reduce overall reaction time and increase overall yield