Preparation, Thermodynamic and Relaxometry Studies for Metal Complexes of Derivatives of DTPA

• Main Authors: Lee, Chien-Hsun, 李建勳
• Other Authors: Yun-Ming Wang
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/45545781663238436535

碩士 === 高雄醫學院 === 藥學研究所 === 86 === Three linear derivatives of diethylenetriamine-N,N,N, N,N -pentaacetic acid(DTPA), N,N-ethylene- N,N-tri- methylenetriamine- N,N,N,N,N-pentaacetic acid(ETTPA), N,N -trimethylene- N,N-trimethylenetriamine- N,N,N,N,N- pentaacetic acid(TETTPA) and N,N-trimethylene- N,N-tetra- methylenetriamine- N,N,N,N,N-pentaacetic acid (TMTTPA) were synthesized. Their protonation constants were determined by potentiometric titration in 0.10 mol dm-3 Me4NNO3 and by NMR pH titration at 25.0  0.1C. The stability constants of calcium( II), zinc(II), copper(II) and gadolinium(III) complexes with those ligands were also investigated quantitatively by the potentiometric technique. The selectivity constants of the ETTPA, TETTPA and TMTTPA for Gd(III) over endogenously available metal ions(i.e. Ca2+, Zn2+ and Cu2+) were calculated and discussed. Spin-lattice relaxivity R1(20MHz, 37.0  0.1C) for Gd(III) complexes was also determined at different pH range. The [Gd(ETTPA)]2-, [Gd(DTPA)]2- and [Gd(DTPA-BMA)] complexes have similar relaxivity values, suggesting that they have similar inner-sphere water molecule and coordination numbers. 17O NMR shifts showed that the [Dy(ETTPA)]2- complex had one inner-sphere water molecule. The observed relaxivity values decrease with increasing pH in the acid region below pH 3, when a [Gd(ETTPA)]2- complex become fully formed, the relaxivity value became invariant. The influence of R1 values at different temperature range was also discussed.