Evaluation of the utility of brain slice methods to study brain penetration
Evaluation of the utility of brain slice methods to study brain penetration
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DOI：
10.1124/dmd.105.007914
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发表时间：
2006-05-01
影响因子：
3.9
通讯作者：
Liu, XR
中科院分区：
文献类型：
--
作者：
Becker, S;Liu, XR
本研究的目的是评价脑组织切片的效用，以确定血浆和脑组织非特异性结合对脑-血浆比（K-p）的影响。使用McIlumbus组织切碎机（Surrey，UK）制备小鼠或大鼠脑切片（400 μ m），并在37 ℃下与1 μ g/ml化合物在生理缓冲液中孵育，以确定缓冲液与切片的浓度比，即，脑组织中的未结合分数（f（u，切片））或血浆中的未结合分数，以确定切片与血浆浓度比（C-切片/C-血浆）。使用平衡透析法测定血浆中的未结合分数f（u，血浆）。分别在小鼠和大鼠中检查了13种和8种模型化合物的脑-血浆比的体外-体内相关性。C-slice/C-plasma和f（u，plasma）/f（u，slice）预测大鼠的K-p，C-slice/C-plasma预测FVB小鼠的非P-糖蛋白底物的K-p在3倍以内，但过度预测P-糖蛋白底物的K-p超过3倍。然而，C-切片/C-血浆预测了mdr 1a/1b基因敲除小鼠的非P-糖蛋白和P-糖蛋白底物的K-p。我们目前的研究表明，脑切片方法可用于区分具有低Kp的化合物是否是由于相对于血浆蛋白与脑组织的非特异性结合较低的影响，或者是由于血脑屏障处的外排转运。
The objective of this study was to evaluate the utility of brain tissue slices to determine the effect of plasma and brain tissue nonspecific binding on the brain-to-plasma ratio (K-p). Mouse or rat brain slices ( 400 mu m) were prepared using a McIlwain tissue chopper ( Surrey, UK) and incubated with 1 mu g/ml of compound at 37 degrees C either in a physiological buffer to determine the buffer-to-slice concentration ratio, i.e., unbound fraction in brain tissue (f(u, slice)), or in plasma to determine the slice-to-plasma concentration ratio (C-slice/C-plasma). The unbound fraction in plasma, f(u,plasma), was determined using equilibrium dialysis. In vitro-in vivo correlation of the brain-to-plasma ratio was examined for 13 and eight model compounds in mice and rats, respectively. C-slice/C-plasma and f(u,plasma)/f(u,slice) predicted the K-p in rats, and C-slice/C-plasma predicted the K-p in FVB mice for non-P-glycoprotein substrates within 3-fold but overpredicted K-p for P-glycoprotein substrates by more than 3-fold. However, C-slice/C-plasma predicted the K-p in mdr1a/1b knockout mice for both non-P-glycoprotein and P-glycoprotein substrates. Our present study demonstrates that a brain slice method can be used to differentiate whether a compound having a low Kp is due to the effect of low nonspecific binding to brain tissue relative to plasma proteins or because of efflux transport at the blood-brain barrier.