ABSTRACT

Bifunctional chelators (BFCs), which can form a bond to both a radiometal ion and a targeting vector, are essential for the development of efficient radiopharmaceuticals. The proper BFC must be matched with a specific radiometal. It is the crucial aspects of the radiometal-chelator complex that are relevant to the design of radiopharmaceuticals, such as thermodynamic stability, kinetic inertness, and complexation kinetics. The DOTA (1,4,7,10-tetrazacyclodecane-1,4,7,10-tetracetic acid) chelator is currently the gold standard, in wide use for radionuclides tri positive radiometals such as ⁶⁸Ga³⁺, ¹¹¹In³⁺, ¹⁷⁷Lu³⁺, ^86/90Y³⁺, and ^44/47Sc³⁺. This study aims to determine the reactivity index data of DOTA chelator such as encompassing ionization potential (IP), electron affinity (EA), chemical hardness (η), electro-donating power (ω⁻), electro-accepting power (ω⁺) by using of density functional theory (B3LYP functional) and basis sets 6-311G(d)/SDD. As a result of DFT calculations, DOTA shows characteristics of a hard chelator, thus following the ionization of the carboxylic acid groups, the resultant amino-polycarboxylic acid exhibits a high affinity chelating agent for trivalent and divalent cations.