Complexation of Scandium with Oxabis(ethylenenitrilo)tetramethylenephosphonic Acid and Applicability of Its 44Sc-Labelled Analogue as Bone-Seeking Agent

Russian Journal of General Chemistry - The regularities of complexation of scandium with oxabis(ethylenenitrilo)tetramethylenephosphonic acid (OBEP), which is actively used nowadays in the clinical...     

2,5-Diamino-5,5-diphosphonovaleric Acid as a Ligand for an Osteotropic <Superscript>188</Superscript>Re Radiopharmaceutical

A modified method for the preparation of 2,5-diamino-5,5-diphosphonovaleric acid (DADP5) has been developed in the search for new synthetically available organic ligands to produce ¹⁸⁸Re radiopharmaceuticals with an increased accumulation in the bone tissue. Interaction of the obtained acid with ¹⁸⁸Re was studied by radio-TLC. An optimal system for separating unbound ¹⁸⁸Re and labeled complex in a yield of at least 95% was found. The biological distribution of ¹⁸⁸Re-DADP5 was studied based on direct radiometric data. The osteotropicity of ¹⁸⁸Re-DADP5 and its increased accumulation in bone fracture sites, which represent oncological pathology models, was detected at a level comparable to known radiopharmaceuticals.     

Separation of 44Sc from 44Ti in the Context of A Generator System for Radiopharmaceutical Purposes with the Example of [44Sc]Sc-PSMA-617 and [44Sc]Sc-PSMA-I&T Synthesis

Today, ⁴⁴Sc is an attractive radionuclide for molecular imaging with PET. In this work, we evaluated a ⁴⁴Ti/⁴⁴Sc radionuclide generator based on TEVA resin as a source of ⁴⁴Sc. The generator prototype (5 MBq) exhibits high ⁴⁴Ti retention and stable yield of ⁴⁴Sc (91 ± 6 %) in 1 mL of eluate (20 bed volumes, eluent—0.1 M oxalic acid/0.2 M HCl) during one year of monitoring (more than 120 elutions). The breakthrough of ⁴⁴Ti did not exceed 1.5 × 10⁻⁵% (average value was 6.5 × 10⁻⁶%). Post-processing of the eluate for further use in radiopharmaceutical synthesis was proposed. The post-processing procedure using a combination of Presep^® PolyChelate and TK221 resins made it possible to obtain ⁴⁴Sc-radioconjugates with high labeling yield (≥95%) while using small precursor amounts (5 nmol). The proposed method takes no more than 15 min and provides ≥90% yield relative to the ⁴⁴Sc activity eluted from the generator. The labeling efficiency was demonstrated on the example of [⁴⁴Sc]Sc-PSMA-617 and [⁴⁴Sc]Sc-PSMA-I&T synthesis. Some superiority of PSMA-I&T over PSMA-617 in terms of ⁴⁴Sc labeling efficiency was demonstrated (likely due to presence of DOTAGA chelator in the precursor structure). It was also shown that microwave heating of the reaction mixture considerably shortened the reaction time and improved radiolabeling yield and reproducibility of [⁴⁴Sc]Sc-PSMA-617 and [⁴⁴Sc]Sc-PSMA-I&T synthesis.     

Evaluation of Applicability of Aminodiphosphonic Acids for the Development of Bone-Seeking 68Ga-Radiopharmaceuticals

Russian Journal of General Chemistry - The binding of 68Ga to two organic ligands containing aminodiphosphonic groups (1,7-diamino-4-oxaheptane-1,1,7,7-tetraphosphonic and...     

Determination of ionic 68Ga impurity in radiopharmaceuticals: major revision of radio-HPLC methods

Journal of Radioanalytical and Nuclear Chemistry - Releasing radionuclide elements from nuclear activities became an important issue. Preparation of activated charcoal-Prussian blue nanoparticles...