Adzamli K, Dorshow R B, Hynes M R, Li D, Nosco D L, Adams M D
Medical Imaging Division, Mallinckrodt, Inc., St. Louis MO, USA.
J Magn Reson Imaging. 1997 Jan-Feb;7(1):204-8. doi: 10.1002/jmri.1880070131.
A blood-persistent particulate paramagnetic contrast agent has been formulated via size stabilization of manganese-substituted hydroxylapatite by a polyethylene glycol (PEG) bearing a terminal diphosphonate. At high PEG surface densities (35-40 mol%), particles with mean diameter 8 +/- 2 nm were obtained. Relaxivities of autoclaved samples (at 20 MHz proton Lamor frequency) were R1 = 18.7 +/- .8 mM-1 sec-1 and R2 = 22.3 +/- .7 mM-1 sec-1. The formulation persisted in rabbit blood with a biphasic clearance profile. Half-lives (with amplitudes in parenthesis) were 4 +/- 1 minutes (55%), and 49 +/- 3 minutes (45%), respectively, for the two phases. A dose of 40 mumol Mn/kg body weight enhanced the signal from rabbit vasculature for more than 45 minutes on MR angiograms. Thus, PEG-modified MnHA particles may find use as T1 agents for MR angiography.
一种血液持久性微粒顺磁性造影剂是通过用带有末端二膦酸盐的聚乙二醇（PEG）对锰取代的羟基磷灰石进行尺寸稳定化而制备的。在高PEG表面密度（35 - 40摩尔%）下，获得了平均直径为8±2纳米的颗粒。高压灭菌样品（在20兆赫质子拉莫尔频率下）的弛豫率为R1 = 18.7±0.8毫摩尔-1秒-1和R2 = 22.3±0.7毫摩尔-1秒-1。该制剂在兔血液中具有双相清除曲线。两个阶段的半衰期（括号内为幅度）分别为4±1分钟（55%）和49±3分钟（45%）。40微摩尔锰/千克体重的剂量在磁共振血管造影上使兔血管系统的信号增强超过45分钟。因此，PEG修饰的MnHA颗粒可作为磁共振血管造影的T1剂。
