大鼠稳态脑分布模型评价药物的血脑屏障通透性

Assessment of blood brain barrier penetration of drugs using a rat steady-state brain distribution model

目的建立大鼠稳态脑分布模型用于评价安替比林、阿替洛尔和ZZB系列新药候选化合物的稳态脑分布和血脑屏障通透性。方法大鼠静脉推注负荷剂量的药物后恒量输注使血药浓度达到稳态,取血和脑组织样品,LC-MS/MS定量测定血浆和脑组织药物浓度,计算稳态脑血比值(Kp值)。在Caco-2单层细胞体外模型上评价受试药物的双向跨膜通透性,计算表观通透系数(Papp)。结果安替比林和阿替洛尔分别为已知的血脑屏障易通透和难通透药物。安替比林的平均稳态脑分布浓度为(2561±125)ng/g,Kp值为0.93±0.04。阿替洛尔则分别为(20.1±0.8)ng/g和0.015±0.002。安替比林的Kp值约为阿替洛尔的60倍。ZZB系列化合物的结构相似,但Kp值的差异较大,从0.044到6.41,并与Caco-2细胞模型的Papp值不相关。结论建立的大鼠稳态脑分布模型可快速形成稳态血浆浓度,适用于药物血脑屏障通透程度的评价,方法简单、可靠且经济。

Objective To develop a steady-state brain distribution model in rats and to assess the blood brain barrier（BBB）penetration of antipyrine,atenolol and a group of ZZB candidate compounds. Methods Antipyrine,atenolol and ZZB compounds were administered to rats by an initial iv bolus dose（loading dose）followed by iv infusion at a constant rate for 30-40 min to reach steady-state plasma kinetics. The blood and brain tissue samples were then collected. The steady-state concentrations of the samples were measured by LC-MS/MS. The steady-state ratio of brain to plasma concentration（Kp）was calculated. The drugs and candidate compounds were also tested with Caco-2 cell model and the apparent bidirectional transport permeability coefficient（Papp） was obtained. Results Antipyrine and atenolol were known as drugs with high and low BBB penetration properties respectively. The mean brain concentrations of antipyrine and atenolol at steady-state were（2561 ± 125）and（20.1±0.8）ng/g with the Kpvalues of 0.93± 0.04 and 0.015 ± 0.002,respectively. The Kpvalue of antipyrine was about 60 folds higher than that of atenolol. Despite the similar structures of ZZB compounds,the Kpvalues were varied in the range from 0.044 to 6.41. The Kpvalues were not correlated with Pappvalues yielded from Caco-2 cell model. Conclusion The established rat steady-state brain distribution model is simple,reliable and could significantly reduce the animal use. It is a practical in vivo model for assessment of BBB penetration of drugs.