银杏内酯B前体药物的脑靶向性研究

On Brain targeting research of ginkgolide B prodrug

目的考察银杏内酯B前体药物(PGB)的脑靶向性,并探究其靶向机制。方法采用LC-MS/MS考察大鼠尾静脉注射PGB后的脑部药动学规律并评价其脑靶向性;采用伊文斯蓝法观察PGB对不完全性脑缺血小鼠脑毛细血管通透性的影响;HPLC法测定PGB在正辛醇-水体系的分配系数(log P);MVD分子对接软件计算PGB与P-糖蛋白(P-gp)的体外结合力;定磷法检测PGB对人P-gp膜ATP酶活性的影响。结果以治疗有效性和靶向指数评价PGB的脑靶向效率达6.87和4.14;PGB预防给药可有效降低不完全性脑缺血小鼠的脑毛细血管通透性(P<0.05);PGB的log P为1.03,高于GB的0.61;分子对接计算表明PGB与P-gp结合力大于GB,其Mol Dock Score分别为-143.36、-116.40 KJ·mol-1;ATP酶活性分析提示PGB、GB均能提高P-gp ATP酶活性,其Km值分别为237.75、841.24μmol·L-1,PGB与P-gp亲和力高于GB。结论 PGB具有脑靶向性,其靶向性提高一方面得益于其脂溶性提高,PGB在脑部渗透量增加;另一方面可能为PGB明显提高P-gp ATP酶活性,从而抑制P-gp对GB的外排作用。

Aim To investigate the brain targeting of ginkgolide B prodrug（ PGB） and its mechanism.Methods The liquid chromatography tandem mass spectrometry（ LC-MS / MS） method was applied to investigate the pharmacokinetics of PGB in rat brain tissue after intravenous injection of PGB. Also the brain targeting was evaluated on the basis of the pharmacokinetic parameter of PGB. The incomplete cerebral ischemia model was induced in mouse,the effect of PGB on cerebral capillary permeability was observed by Evans blue method. High performance liquid chromatography（ HPLC） was used to determine the partition coefficients（ log P） of PGB in octanol-water system. PGB and P-glycoprotein（ P-gp） was docked by using Molegro Virtual Docker（ MVD） software to predict its binding abilities with P-gp. The interaction of PGB with ATPase activity of human P-gp membrane was estimated by measuring inorganic phosphate liberation.Results The brain targeting of PGB was evaluated by treatment effective（ TA） and drug targeting index（ DTI）,the calculated value were 6. 87 and 4. 14 respectively. Preventive medication of PGB could significantly decrease cerebral capillary permeability（ P 〈0. 05）. The lipo-hydropartition coefficient of PGB was higher than that of GB,their log P data were 1. 03 and0. 61 respectively. PGB displayed the stronger binding affinity with P-gp than GB according to the molecular docking calculations,their Mol Dock Score toward P-gp were- 143. 36 and- 116. 40KJ·mol^- 1respectively.ATP-hydrolisis showed that PGB increased ATPase activity with a Kmof approximately 237. 75 μmol ·L^- 1,however GB with a Kmof approximately 841. 24μmol·L^- 1. PGB might interact with P-gp with a higher affinity and exhibit more effect than GB. Conclusion PGB is characterized by its brain targeting.Higher liposolubility of PGB results in good blood-brain permeability,which is advantageous to its brain targeting. Besides,PGB can effectively inhibit the efflux effect of P-gp to GB because of its increased P-gp ATPase activity.ting. Besides,PGB can effectively inhibit the efflux effect of P-gp to GB because of its increased P-gp ATPase activity.