title: Insight into the structure and stability of Tc and Re DMSA complexes: A computational study.
abstract: Meso-2,3-dimercaptosuccinic acid (DMSA) is used in nuclear medicine as ligand for preparation of diagnostic and therapy radiopharmaceuticals. DMSA has been the subject of numerous investigations during the past three decades and new and significant information of the chemistry and pharmacology of DMSA complexes have emerged. In comparison to other ligands, the structure of some DMSA complexes is unclear up today. The structures and applications of DMSA complexes are strictly dependent on the chemical conditions of their preparation, especially pH and components ratio. A computational study of M-DMSA (M=Tc, Re) complexes has been performed using density functional theory. Different isomers for M(V) and M(III) complexes were studied. The pH influence over ligand structures was taken into account and the solvent effect was evaluated using an implicit solvation model. The fully optimized complex syn-endo Re(V)-DMSA shows a geometry similar to the X-ray data and was used to validate the methodology. Moreover, new alternative structures for the renal agent99mTc(III)-DMSA were proposed and computationally studied. For two complex structures, a larger stability respect to that proposed in the literature was obtained. Furthermore, Tc(V)-DMSA complexes are more stable than Tc(III)-DMSA proposed structures. In general, Re complexes are more stable than the corresponding Tc ones.
authors.affiliation: Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de La Habana, Avenida Salvador Allende No 1110 entre Infanta y Avenida Rancho Boyeros, Quinta de los Molinos, A.P. 6163, La Habana, Cuba; Department of Chemistry, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hernández-Valdés
authors.affiliation: Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de La Habana, Avenida Salvador Allende No 1110 entre Infanta y Avenida Rancho Boyeros, Quinta de los Molinos, A.P. 6163, La Habana, Cuba.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Blanco-González
authors.affiliation: Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de La Habana, Avenida Salvador Allende No 1110 entre Infanta y Avenida Rancho Boyeros, Quinta de los Molinos, A.P. 6163, La Habana, Cuba.
authors.forename: Ariel
authors.initials: A
authors.lastname: García-Fleitas
authors.affiliation: Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de La Habana, Avenida Salvador Allende No 1110 entre Infanta y Avenida Rancho Boyeros, Quinta de los Molinos, A.P. 6163, La Habana, Cuba.
authors.forename: Zalua
authors.initials: Z
authors.lastname: Rodríguez-Riera
authors.affiliation: Department of Chemistry, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Meola
authors.affiliation: Department of Chemistry, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Alberto
authors.affiliation: Instituto Superior de Tecnologías y Ciencias Aplicadas, Universidad de La Habana, Avenida Salvador Allende No 1110 entre Infanta y Avenida Rancho Boyeros, Quinta de los Molinos, A.P. 6163, La Habana, Cuba. Electronic address: ulises.jauregui@infomed.sld.cu.
authors.forename: Ulises
authors.initials: U
authors.lastname: Jáuregui-Haza
mesh_terms: D019295:Computational Biology; D006801:Humans; D008024:Ligands; D011877:Radionuclide Imaging / Q000379:methods*; D019275:Radiopharmaceuticals / Q000737:chemistry* / Q000627:therapeutic use; D004113:Succimer / Q000737:chemistry*
chemical_list: D008024:Ligands; D019275:Radiopharmaceuticals; D004113:Succimer
keywords: DFT calculation; DMSA; Radiopharmaceuticals; Re and Tc complexes