丹参酮Ⅱ_(A)聚合物脂质纳米粒制备及脑部药物递送研究

Study on preparation of tanshinone ⅡA polymer lipid nanoparticles and brain delivery

目的为了改善丹参酮Ⅱ_(A)(TanⅡ_(A))的溶解性、增加脑组织中的药物浓度,制备TanⅡ_(A)聚合物脂质纳米粒(TanⅡ_(A)-PLNs)并进行体外释放、药动学、脑组织分布研究。方法建立TanⅡ_(A)含量测定的高效液相色谱(HPLC)法,以纳米制剂的包封率和粒径为指标,优化TanⅡ_(A)-PLNs的制备工艺,分别优化TanⅡ_(A)与蛋黄磷脂(Egg-PC)的比例、Egg-PC与聚乳酸-羟基乙酸共聚物(PLGA)的比例、有机相与水相的比例;进行TanⅡ_(A)-PLNs的处方验证、稳定性考察、体外释放考察。建立TanⅡ_(A)在血浆和脑匀浆中的液-质联用(LC-MS)检测方法。SPF级雄性SD大鼠6只,随机分为2组,给药前12 h禁食,一组ig 25 mg·kg^(-1)的TanⅡ_(A)混悬液,另一组尾iv 5 mg·kg^(-1)的TanⅡ_(A)-PLNs溶液,于给药后5、15、30、60、120、240、360、480、720 min眼眶取血约0.5 m L,LC-MS法进行药动学检测。取KM小鼠4只,尾iv Di R标记的Tan Ⅱ_(A)-PLNs,给药30、60、120、240 min后处死解剖,通过荧光成像观察Tan Ⅱ_(A)-PLNs在组织中的分布情况。取KM小鼠12只,随机分成4组,给药前12 h禁食,尾iv 2.5 mg·kg^(-1)的TanⅡ_(A)-PLNs溶液,于给药后30、60、120、240 min处死小鼠,剥离完整大脑组织,称质量,加入2倍超纯水匀浆,LC-MS法检测TanⅡ_(A)水平。结果TanⅡ_(A)-PLNs的最优处方为TanⅡ_(A)∶Egg-PC为1∶4、Egg-PC∶PLGA为5∶2、有机分散体系∶水分散体系为1∶15。以Egg-PC/PLGA作为脂质纳米粒的膜材,采用纳米粒沉淀法制备的TanⅡ_(A)-PLNs的平均粒径为272 nm,Zeta电位为-4.93 m V,包封率为88.2%,载药量为18%。在避光、干燥(室温)的条件下Tan Ⅱ_(A)-PLNs冻干粉稳定。Tan Ⅱ_(A)原料药在48 h内释放完全,累积释放率为(93.75±0.75)%,与Korsmeyer-Peppas释放方程拟合程度较好;Tan Ⅱ_(A)-PLNs在400 h左右释放完全,累积释放率为(89.44±2.22)%,与零级释放方程拟合度最好。药动学结果表明,大鼠尾iv TanⅡ_(A)-PLNs给药剂量是ig TanⅡ_(A)原料药剂量的1/5,TanⅡ_(A)-PLNs的AUC_(0-t)和t_(1/2B)是TanⅡ_(A)原料药的2.8和1.5倍。组织分布实验结果显示,30 min时肝组织显示荧光;60 min时脑组织显示出荧光,120 min时脑组织荧光最强,240 min时脑组织荧光变弱。TanⅡ_(A)-PLNs给药2 h后,TanⅡ_(A)脑匀浆质量浓度为235.5 ng·g^(-1)。结论制备的TanⅡ_(A)-PLNs均一稳定,包封率较高,聚合物脂质纳米颗粒的应用提高了TanⅡ_(A)的血药浓度,可增加药物在脑部的暴露。

Objective Tanshinone Ⅱ_(A)polymeric lipid nanoparticles(TanⅡ_(A)-PLNs)were prepared for improving the solubility and drug concentration in brain tissue to increase drug brain exposure.In vitro release,pharmacokinetics and brain tissue distribution were studied.Method A high performance liquid chromatography(HPLC)method was established to determine the content of TanⅡ_(A),and the preparation process of TanⅡ_(A)-PLNs was optimized by taking the encapsulation rate and particle size of nano-preparations as indexes.The proportion of TanⅡ_(A)to Egg-PC,Egg-PC to polylactic acid-hydroxyacetic acid copolymer(PLGA)and organic phase to water phase were optimized respectively.The prescription validation,stability and in vitro release of TanⅡ_(A)-PLNs were investigated.To establish a method for the determination of TanⅡ_(A)in plasma and brain homogenates by liquid-mass spectrometry(LC-MS).Six SPF male SD rats were randomly divided into two groups,one group was given 25 mg·kg^(-1) TanⅡ_(A)suspension,the other group was given 5 mg·kg^(-1) TanⅡ_(A)-PLNs solution.At 5,15,30,60,120,240,360,480,720 min after administration,about0.5 m L blood was collected from orbit,and pharmacokinetic detection was performed by LC-MS.Four KM mice were selected and TanⅡ_(A)-PLNs labeled with iv Di R were sacrificed 30,60,120 and 240 min after administration,and the distribution of TanⅡ_(A)-PLNs in tissues was observed by fluorescence imaging.Twelve KM mice were randomly divided into four groups,fasted 12 h before administration,and treated with 2.5 mg·kg^(-1) TanⅡ_(A)-PLNs solution in tail iv.The mice were sacrificed 30,60,120 and 240 min after administration.The intact brain tissues were stripped,weighed,and the level of TanⅡ_(A)was detected by LC-MS.Results Egg-PC/PLGA(5:2)were used as membrane materials of Tan Ⅱ_(A)-PLNs nanoparticles,and the volume ratio of organic phase to water phase was 1:15.The particle size,zeta potential,entrapment efficiency and drug loading capacity of Tan Ⅱ_(A)-PLNs were 272 nm,-4.93 m V,88.2%,18%respectively.TanⅡ_(A)-PLNs freeze-dried powder is stable under dry conditions(room temperature)and away from light.Pharmacokinetics showed that the AUC_(0-t)and t_(1/2B)of Tan Ⅱ_(A)-PLNs were 2.8 and 1.5 times higher than free Tan Ⅱ_(A)even the dose difference of administration was 1/5 times.The results of tissue distribution experiment showed that the liver tissue showed fluorescence at 30 min.The brain tissue showed fluorescence at 60 min,the fluorescence was the strongest at 120 min,and the fluorescence became weak at 240 min.The plasma concentration of Tan Ⅱ_(A)reached 235.5 ng/g after 2 h of Tan Ⅱ_(A)-PLNs administration.Conclusion Tan Ⅱ_(A)-PLNs were uniform and stable,and had a higher entrapment efficiency.In vivo pharmacokinetic parameters showed that the application of polymeric lipid nanoparticles improved the concentration of Tan Ⅱ_(A)in brain tissue and increased the exposure of the drug in the brain.