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001-es BibID:	BIBFORM087593
Első szerző:	Sarka Lajos
Cím:	The rates of the exchange reactions between [Gd(DTPA)](2-) and the endogenous ions Cu2+, and Zn2+: A kinetic model for the prediction of the in vivo stability of [Gd(DTPA)](2-) used as a contrast agent in magnetic resonance imaging / L. Sarka, L. Burai, E. Brücher
Dátum:	2000
ISSN:	0947-6539 1521-3765
Megjegyzések:	The kinetic stability of the complex [Gd(DTPA)]2?(H5DTPA=diethylenetriamine?N,N,N·,Nı,Nı?pentaacetic acid), used as a contrast?enhancing agent in magnetic resonance imaging (MRI), is characterised by the rates of the exchange reactions that take place with the endogenous ions Cu2+and Zn2+. The reactions predominantly occur through the direct attack of Cu2+and Zn2+on the complex (rate constants are 0.93?0.17?M?1s?1and (5.6?0.4)?10?2M?1s?1, respectively). The proton?assisted dissociation of [Gd(DTPA)]2?is relatively slow (k1=0.58?0.22?M?1s?1), and under physiological conditions the release of Gd3+predominantly occurs through the reactions of the complex with the Cu2+and Zn2+ions. To interpret the rate data, the rate?controlling role of a dinuclear intermediate was assumed in which a glycinate fragment of DTPA is coordinated to Cu2+or Zn2+. In the exchange reactions between [Gd(DTPA)]2?and Eu3+, smaller amounts of Cu2+and Zn2+and their complexes with the amino acids glycine and cysteine have a catalytic effect. In a model of the fate of the complex in the body fluids, the excretion and the "dissociation" of [Gd(DTPA)]2?are regarded as parallel first?order processes, and by 10 h after the intravenous administration the ratio of the amounts of "dissociated" and excreted [Gd(DTPA)]2?is constant. From about this time, 1.71?% of the injected dose of [Gd(DTPA)]2?is "dissociated". The results of equilibrium calculations indicate that the Gd3+released from the complex is in the form of Gd3+?citrate.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk chelates contrast agents exchange reactions gadolinium kinetics
Megjelenés:	Chemistry European Journal. - 6 : 4 (2000), p. 719-724. -
További szerzők:	Burai László Brücher Ernő (1935-) (vegyész)
Pályázati támogatás:	FKFP 0448/1997 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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