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001-es BibID:	BIBFORM081486
Első szerző:	Baranyai Zsolt (vegyész)
Cím:	The Role of Equilibrium and Kinetic Properties in the Dissociation of Gd[DTPA-bis(methylamide)] (Omniscan) at near to Physiological Conditions / Zsolt Baranyai, Ernő Brücher, Fulvio Uggeri, Alessandro Maiocchi, Imre Tóth, Melinda Andrási, Attila Gáspár, László Zékány, Silvio Aime
Dátum:	2015
ISSN:	0947-6539 1521-3765
Megjegyzések:	[Gd(DTPA?BMA)] is the principal constituent of Omniscan, a magnetic resonance imaging (MRI) contrast agent. In body fluids, endogenous ions (Zn2+, Cu2+, and Ca2+) may displace the Gd3+. To assess the extent of displacement at equilibrium, the stability constants of DTPA?BMA3? complexes of Gd3+, Ca2+, Zn2+, and Cu2+ have been determined at 37?°C in 0.15?M NaCl. The order of these stability constants is as follows: GdL?CuL>ZnL?CaL. Applying a simplified blood plasma model, the extent of dissociation of Omniscan (0.35?mM [Gd(DTPA?BMA)]) was found to be 17?% by the formation of Gd(PO4), [Zn(DTPA?BMA)]? (2.4?%), [Cu(DTPA?BMA)]? (0.2?%), and [Ca(DTPA?BMA)]? (17.7?%). By capillary electrophoresis, the formation of [Ca(DTPA?BMA)]? has been detected in human serum spiked with [Gd(DTPA?BMA)] (2.0?mM) at pH?7.4. Transmetallation reactions between [Gd(DTPA?BMA)] and Cu2+ at 37?°C in the presence of citrate, phosphate, and bicarbonate ions occur by dissociation of the complex assisted by the endogenous ligands. At physiological concentrations of citrate, phosphate, and bicarbonate ions, the half?life of dissociation of [Gd(DTPA?BMA)] was calculated to be 9.3?h at pH?7.4. Considering the rates of distribution and dissociation of [Gd(DTPA?BMA)] in the extracellular space of the body, an open two?compartment model has been developed, which allows prediction of the extent of dissociation of the GdIII complex in body fluids depending on the rate of elimination of the contrast agent.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk complex stability gadolinium kinetics magnetic resonance imaging reaction mechanisms
Megjelenés:	Chemistry-A European Journal. - 21 : 12 (2015), p. 4789-4799. -
További szerzők:	Brücher Ernő (1935-) (vegyész) Uggeri, Fulvio Maiocchi, Alessandro (vegyész) Tóth Imre (1950-) (vegyész) Andrási Melinda (1979-) (gyógyszerész) Gáspár Attila (1970-) (vegyész, kémikus) Zékány László (1948-) (vegyész) Aime, Silvio
Pályázati támogatás:	TÁMOP 4.2.4. A/2-11-1-2012-0001 TÁMOP A2-MZPD-12-0038 Egyéb OTKA K109029 OTKA OTKA K111932 OTKA OTKA PD83071 OTKA TÁMOP-4.2.2 A-11/1/KONV-2012-0043 TÁMOP
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001-es BibID:	BIBFORM047932
Első szerző:	Baranyai Zsolt (vegyész)
Cím:	Equilibrium, Kinetic and Structural Studies of AAZTA Complexes with Ga3+, In3+ and Cu2+ / Zsolt Baranyai, Fulvio Uggeri, Alessandro Maiocchi, Giovanni B. Giovenzana, Camilla Cavallotti, Anett Takács, Imre Tóth, István Bányai, Attila Bényei, Ernő Brücher, Silvio Aime
Dátum:	2013
Megjegyzések:	A detailed study of the structures, thermodynamic stabilities and kinetics of the dissociation of Ga3+, In3+ and Cu2+ complexes formed with the heptadentate ligand AAZTA is reported. The stability constants (logKML) of the AAZTA complexes of Ga3+, In3+ and Cu2+ are 22.18, 29.58 and 22.27, respectively, which suggests that the seven-membered-ring skeleton is suited to the accommodation of these metal ions. The solid-state structure of Cu(H2AAZTA)]?H2O shows a distorted octahedral coordination. The equatorial coordination sites of Cu2+ are occupied by one of the ring N atoms, a water O atom, one of the carboxylate O atoms and the N atom of the iminodiacetate moiety. The other ring N atom and thecarboxylate O atom of the iminodiacetate moiety coordinate to the Cu2+ in the axial positions. In the pH range 4.5?8.5, Ga3+ is present in the form of the highly stable [Ga(AAZTA)OH]2? (log ?GaLH?1 = 17.69) The exchange reactions of [Ga(AAZTA)OH]2? with Cu2+ and transferrin are very slow and mainly occur through the spontaneous dissociation of the complex close to physiological conditions. The half-life for the dissociation of [Ga(AAZTA)OH]2? is t1/2 = 23 h at pH = 7.5 and 25 ?C in 0.025 M NaHCO3 and 0.15 M NaCl. The high conditional stability, fast formation and sufficiently slow dissociation of [Ga(AAZTA)OH]2? represent promising properties for the complexation and diagnostic applications of radioactive Ga isotopes.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Gallium Indium Copper Complexation Thermodynamics Kinetics Radiopharmaceuticals Imaging agents Molekulatudomány Doktori iskola
Megjelenés:	European Journal Of Inorganic Chemistry. - 2013 : 1 (2013), p. 147-162. -
További szerzők:	Uggeri, Fulvio Maiocchi, Alessandro (vegyész) Giovenzana, Giovanni Battista Cavallotti, Camilla Takács Anett Tóth Imre (1950-) (vegyész) Bányai István (1953-) (vegyész) Bényei Attila (1962-) (vegyész) Brücher Ernő (1935-) (vegyész) Aime, Silvio
Pályázati támogatás:	K-84291 OTKA TÁMOP-4.2.1/B-09/1/KONV-2010-0007 TÁMOP Bimodális kontrasztanyagok tervezése, előállítása és komplexeik fizikai-kémiai tulajdonságaik jellemzése TÁMOP-4.2.2/B-10/1-2010-0024 TÁMOP Kémiai Tudományok Doktori Iskola EU COST (TD1004) "Theragnostics Imaging and Therapy" Action Program. Egyéb HU11MO2-TET_10-1-2011-0202 Egyéb
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001-es BibID:	BIBFORM078703
Első szerző:	Vágner Adrienn (vegyész, kémikus)
Cím:	Equilibrium Thermodynamics, Formation, and Dissociation Kinetics of Trivalent Iron and Gallium Complexes of Triazacyclononane-Triphosphinate (TRAP) Chelators: Unraveling the Foundations of Highly Selective Ga-68 Labeling / Adrienn Vágner, Attila Forgács, Ernő Brücher, Imre Tóth, Alessandro Maiocchi, Alexander Wurzer, Hans-Jürgen Wester, Johannes Notni, Zsolt Baranyai
Dátum:	2018
ISSN:	2296-2646
Megjegyzések:	In order to rationalize the influence of FeIII contamination on labeling with the 68Ga eluted from 68Ge/68Ga-generator, a detailed investigation was carried out on the equilibrium properties, formation and dissociation kinetics of GaIII- and FeIII - complexes of 1,4,7-triazacyclononane-1,4,7-tris(methylene[2-carboxyethylphosphinic acid]) (H6TRAP). The stability and protonation constants of the [Fe(TRAP)]3? complex were determined by pH-potentiometry and spectrophotometry by following the competition reaction between the TRAP ligand and benzhydroxamic acid (0.15 M NaNO3, 25?C). The formation rates of [Fe(TRAP)] and [Ga(TRAP)] complexes were determined by spectrophotometry and 31P-NMR spectroscopy in the pH range 4.5? 6.5 in the presence of 5?40 fold HxTRAP(x?6) excess (x = 1 and 2, 0.15 M NaNO3, 25?C). The kinetic inertness of [Fe(TRAP)]3? and [Ga(TRAP)]3? was examined by the trans-chelation reactions with 10 to 20-fold excess of HxHBED(x?4) ligand by spectrophotometry at 25?C in 0.15 M NaCl (x = 0,1 and 2). The stability constant of [Fe(TRAP)]3? (logKFeL = 26.7) is very similar to that of [Ga(TRAP)]3? (logKGaL = 26.2). The rates of ligand exchange reaction of [Fe(TRAP)]3? and [Ga(TRAP)]3? with HxHBED(x?4) are similar. The reactions take place quite slowly via spontaneous dissociation of [M(TRAP)]3?, [M(TRAP)OH]4? and [M(TRAP)(OH)2] 5? species. Dissociation half-lives (t1/2) of [Fe(TRAP)]3? and [Ga(TRAP)]3? complexes are 1.1 ? 105 and 1.4 ? 105 h at pH = 7.4 and 25?C. The formation reactions of [Fe(TRAP)]3? and [Ga(TRAP)]3? are also slow due to the formation of the unusually stable monoprotonated [?M(HTRAP)]2? intermediates [?logKGa(HL) = 10.4 and ?logKFe(HL) = 9.9], which are much more stable than the [?Ga(HNOTA)]+ intermediate [?logKGa(HL) = 4.2]. Deprotonation and transformation of the monoprotonated [?(HTRAP)]2? intermediates into the final complex occur via OH?-assisted reactions. Rate constants (kOH) characterizing the OH?-driven deprotonation and transformation of [? Ga(HTRAP)]2? and [?Fe(HTRAP)]2? intermediates are 1.4 ? 105 M?1 s-1 and 3.4 ? 104 ?1s?1, respectively. In conclusion, the equilibrium and kinetic properties of [Fe(TRAP)] and [Ga(TRAP)] complexes are remarkably similar due to the close physico-chemical properties of FeIII and GaIII-ions. However, a slightly faster formation of [Ga(TRAP)] over [Fe(TRAP)] provides a rationale for a previously observed, selective complexation of 68GaIII in presence of excess FeIII.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban chelates gallium iron thermodynamics kinetics reaction mechanism positron emission tomography
Megjelenés:	Frontiers in Chemistry. - 6 (2018), p. 1-12. -
További szerzők:	Forgács Attila (1988-) (vegyész) Brücher Ernő (1935-) (vegyész) Tóth Imre (1950-) (vegyész) Maiocchi, Alessandro (vegyész) Wurzer, Alexander Wester, Hans J. Notni, Johannes Baranyai Zsolt (1977-) (vegyész)
Pályázati támogatás:	GINOP-2.3.3-15-2016-00004 GINOP GINOP-2.3.2-15-2016-00008 GINOP
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