Medicinal Radiopharmaceutical Chemistry of Metal Radiopharmaceuticals

Abstract

Metal complexes have been used as medicinal compounds. Metals have advantageous features over organic compounds. Significant applications of metal complexes are in the field of nuclear medicine. Radiopharmaceuticals are drugs containing radioisotopes used for diagnostic and therapeutic purposes. The generalized targeting strategy for molecular imaging probe consists of three essential parts: (i) reporter unit or payload, (ii) carrier, and (iii) targeting system. Medicinal radiopharmaceutical chemistry pays special consideration to radioisotopes, as a reporter unit for diagnostic application or as a payload for therapeutic application. Targeting is achieved by a few approaches but the most common is the bifunctional chelator approach. While designing a radiopharmaceutical, a range of issues needs to be considered including properties of metal radioisotopes, bifunctional chelators, linkers, and targeting molecules. Designing radiopharmaceuticals requires consideration of two key words: "compounds of biological interest" and "fit for intended use." The ultimate goal is the development of new diagnostic methods and treatment. Diagnostic metal radiopharmaceuticals are used for SPECT and PET applications. Technetium chemistry constitutes a major portion of SPECT and gallium chemistry constitutes a major portion of PET. Therapeutic radiopharmaceuticals can be constructed by using alpha-, beta minus-, or Auger electron-emitting radiometals. Special uses of medicinal radiopharmaceuticals include internal radiation therapy, brachytherapy, immunoPET, radioimmunotherapy, and peptide receptor radionuclide imaging and therapy.

Iron(III)-Tannic Molecular Nanoparticles Enhance Autophagy effect and T1 MRI Contrast in Liver Cell Lines

“…The large negative zeta potential indicates good colloidal stability of the Fe–TA NPs in the aqueous medium 40 . This result is in consistent with the measured log P value of −1.0249, indicating good water solubility 41 . Previously, it has been demonstrated that molecular nanoparticles of Fe–TA complexes exhibit paramagnetism and enhance MRI signal intensity in T 1 -weighted imaging 28 .…”

Quantitative structure property relationships on formation constants of radiometals for radiopharmaceuticals applications

“…The complexity in biological systems, containing circulating blood (pH of 7.4 and 37°C), various proteins and enzymes, and small quantities of radiopharmaceuticals can cause competitive binding and transchelation challenges by these substances [6]. If a radiometal-chelate complex is strong enough in vivo, the complex is typically cleared quickly from the animal through the kidneys/bladder/urine or digestive system/liver/faeces depending on polarity and metabolism [5,27].…”

“…If a radiometal-chelate complex is strong enough in vivo, the complex is typically cleared quickly from the animal through the kidneys/bladder/urine or digestive system/liver/faeces depending on polarity and metabolism [5,27]. Therefore the radiopharmaceuticals must be thermodynamically stable and kinetically inert over the time course of the diagnostic application or therapeutic procedure [6,28]. Combining chemoinformatics and 3D molecular modeling approaches might be very useful for the development of new ligand in metal complexation [29].…”

“…BFCs are covalently attached to the targeting bioactive molecule at one terminus while the second terminus strongly coordinates to the radiometal. The structure and physicochemical properties of radiometalchelate complex can have a significant impact on overall biological properties and in vivo distribution of the targetspecific radiopharmaceuticals [6], hence the knowledge of metal coordination chemistry and ligand structure are of great importance. 64 Cu(II) complexed to pharmaceuticals are used in PET imaging, clinical and therapy applications and in biodistribution studies [7].…”

Molecular dynamics simulation of Fe-NO2 At-alpha mangostin as radiopharmaceutical model for detection of fatty acid synthase in cancer

“…Ga 3 + has a small ionic radius (0.62Å)[ 3 4 ] and compatible with the hole size of the NOTA cavity that leads to the stability of compound complex of Ga 3+- NOTA. [ 2 5 ] This phenomenon is known as a size-match selectivity.…”