ABSTRACT: Recently, macrocycles such as 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) have been observed to form zirconium-89 (89Zr: t½ = 78.4 h, β+: 22.8%, Eβ+max = 901 keV; EC: 77%, Eγ = 909 keV)-complexes with excellent in vivo stability. In this report, we describe (1R,4R,7R,10R)-α,α',α″,α‴-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTMA) as an 89Zr chelator. Using [89Zr]ZrCl4, [89Zr]Zr-DOTMA was prepared in 99% radiochemical yield and a molar activity of 1055 ± 6 MBq/µmol. In vitro studies revealed a LogP value of -2.97± 0.02 and a radiometal complex that was inert when challenged with 1000-fold excess EDTA or high concentrations of biologically relevant m
