- 作者: 王雲銘,歐明鴻,鄭粲煌,劉金昌
- 作者服務機構: Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan, R.O.C.
- 中文摘要: The analysis of 17O NMR transverse relaxation rates and EPR transverse electronic relaxation rates for aqueous solutions of the four DTPA-like (DTPA = diethylenetriamine-N,N,N¢,N2,N2-pentaacetic acid) complexes, [Gd(DTPA-PY)(H2O)]- (DTPA-PY = N¢-(2-pyridylmethyl)), [Gd(DTPA-HP)(H2O)2]- (DTPA-HP = N¢-(2-hydroxypropyl)), [Gd(DTPA-H1P)(H2O)2]- (DTPA-H1P = N¢-(2-hydroxy-1-phenylethyl)) and [Gd(DTPA-H2P)(H2O)2]- (DTPA-H2P = N¢-(2-hydroxy-2-phenylethyl)), at various temperatures allows us to understand the water exchange dynamics of these four complexes. The water-exchange lifetime (tM) parameters for [Gd(DTPA-PY)(H2O)]-, [Gd(DTPA-HP)(H2O)2]-, [Gd(DTPA-H1P)(H2O)2]- and [Gd(DTPA-H2P)(H2O)2]- are of 585, 98, 163, and 69 ns, respectively. Compared with [Gd(DTPA)(H2O)]2- (tM = 303 ns), the tM value of [Gd(DTPA-PY)(H2O)]- is slightly higher, but the other three complexes values are significantly lower than those of [Gd(DTPA)(H2O)]2-. This difference is explained by the fact that the gadolinium(III) complexes of DTPA-HP, DTPA-H1P, and DTPA-H2P have two inner-sphere waters. The 2H longitudinal relaxation rates of the labeled diamagnetic lanthanum complex allow the calculation of its rotational correlation time (tR). The tR values calculated for DTPA-PY, DTPA-HP, DTPA-H1P, and DTPA-H2P are of 127, 110, 142 and 147 ps, respectively. These four values are higher than the value of [La(DTPA)]2- (tR = 103 ps), because the rotational correlation time is related to the magnitude of its molecular weight.
- 英文摘要: --
- 中文關鍵字: MRI contrast agent; Water-exchange lifetime; Rotational correlation time; Gadolinium(III) complexes.
- 英文關鍵字: --