如何比较albumin-bound的效率和nonalbumin-bound造影剂在体内:动态relaxivity的概念。

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港口M, C, Corot中提琴X,罗伯特•P Raynal我Gagneur G

如何比较albumin-bound的效率和nonalbumin-bound造影剂在体内:动态relaxivity的概念。

Radiol投资。2005年9月,40 (9):565 - 73。

PubMed ID

16118549 (在PubMed

]

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原理及目的:本研究的目的是对比,在一只兔子实验模型,模拟一个磁共振(MR)血管造影协议,以下类型的复合效率的信号先生:(1)nonalbumin-bound血池造影剂:P792;(2)弱albumin-bound细胞外对比剂:Gd-BOPTA;和(3)一个强大albumin-bound血池造影剂:MS325。方法:早期分布的两个主要阶段对比剂注射后,即丸阶段(0-15秒接受)和postbolus阶段(1 - 5分钟接受)研究了通过测量在第一个5分钟接受Gd血药浓度。对于MS325 Gd-BOPTA,自由和约束形式的百分比计算整个药动学特征。动态relaxivity 60 MHz的等离子体中的每个造影剂决心2阶段对比剂注射后,即丸阶段和postbolus阶段。结果:注射在相似的条件下,3造影剂在丸阶段有一个类似的概要文件(0-15秒接受)。在1分钟接受,只有38%的Gd-BOPTA保持血液中,而85%的P792是血液中仍然存在。女士- 325有一个中间位置有61%剩余的血液中。在postbolus阶段,各种化合物表现出类似的行为:P792的血浆浓度高于MS325 Gd-BOPTA,即Ci / C0 (P792) > Ci / C0 (MS325) > Ci / C0 (Gd-BOPTA)。 At the peak of the bolus, 75% of MS325 and 93% of Gd-BOPTA was present in free form. This proportion decreased progressively during the postbolus phase, because 5 minutes postinjection, 23% of the free form remained for MS325 and 82% for Gd BOPTA. A significant decrease in dynamic r1 relaxivity was observed at 60 MHz for the products that bind to albumin (Gd-BOPTA and MS325) during the bolus phase. The dynamic relaxivity for MS325 at the bolus phase was 8.6 mMs and 5.2 mMs for Gd-BOPTA. At the postbolus phase, the dynamic relaxivity increased (17.3 mMs for MS325 and 6.7 mMs for Gd-BOPTA). The dynamic relaxivity of P792, which does not bind to albumin, was constantly equal to 26 mMs at each time point of the pharmacokinetic profile (bolus and postbolus phase). CONCLUSIONS: The physicochemical measurements of relaxivity in plasma are made in vitro at a fixed concentration of gadolinium and the value of relaxivity is not necessarily an accurate reflection of the efficiency of the contrast agent in vivo, especially for contrast agents that bind to albumin. Indeed, in vivo, the proportion of free and bound forms of albumin-binding contrast agents varies according to the pharmacokinetic profile, and the relaxivities of albumin-bound and free contrast agents are different. Consequently, the concept of dynamic relaxivity was introduced to compare the efficiency of MS325, Gd-BOPTA, and P792 in vivo. The variation of the dynamic relaxivity of MS325 and Gd-BOPTA between the bolus and postbolus phase is significant (101% for MS325 and 29% for Gd-BOPTA) as a result of the variation in the quantity of bound and free forms during the pharmacokinetic profile. The blood pool agent P792 has different properties, which result from its intravascular retention and its lack of albumin binding. Indeed, contrary to Gd-BOPTA and MS325, the dynamic relaxivity of P792 is higher at the bolus phase (26 mMs) and does not vary during the pharmacokinetic profile. The impact of these different dynamic relaxivities should be integrated in the analysis of the performance of the different classes of contrast agents in clinical MRA protocols.

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药物载体

药物	航空公司	类	生物	药理作用	行动
Gadobenic酸	血清白蛋白	蛋白质	人类	未知的	粘结剂	细节