染料木素MePEG-PLGA共聚物胶束的制备及其药动学研究

Preparation of Genistein-loaded MePEG-PLGA Nano-micelle and its Pharmacokinetics in Rats

关键词:  染料木素  胶束  体外释放  稳定性  药动学

Key words:  genistein  nano-micelle  release in vitro  stability  pharmacokinetics

摘要:

目的 制备染料木素(GEN)MePEG-PLGA共聚物胶束，考察其理化性质、初步稳定性及静脉给药后大鼠体内的药动学行为。方法 采用改良的自乳化溶剂挥发法制备胶束，考察其形态、包封率、载药量、粒径和Zeta电位；采用动态膜透析技术考察其释药行为，并对其释药规律进行拟合；将胶束冻干品置于4 ℃冰箱中保存，分别于放置1 d、10 d、1个月、3个月、6个月后取样，考察其包封率和载药量变化；对健康大鼠尾静脉注射GEN胶束，采用HPLC测定GEN在大鼠体内的血药浓度，采用DAS 2.0软件处理血药浓度数据，SPSS 17.0软件对主要药动学参数进行统计学分析。结果 制备所得胶束的包封率为(84.43±2.93)%，载药量为(2.63±0.91)%，粒径为(63.75±4.12)nm；GEN胶束的释药行为最符合Weibull模型；GEN胶束冻干品6个月渗漏率为2.45%，载药量下降0.18%；大鼠尾静脉注射GEN胶束和GEN乳剂40 mg·kg^-1后，主要药动学参数AUC_0-t分别为(99.46±4.77)mg·L^-1·h和(57.51±1.37)mg·L^-1·h，t_1/2分别为(7.48±1.15)h和(4.95±1.15)h，C_max分别为(16.03±1.20)mg·L^-1和(16.73±1.10)mg·L^-1，CL分别为(0.36±0.02)L·h^-1·kg^-1和(0.67±0.02)L·h^-1·kg^-1。结论 制备所得的GEN胶束形态规整，粒径分布狭窄，包封率较高，具有一定的缓释特征，稳定性良好，并且明显改变了GEN的药动学行为，使其消除减慢，同时提高了药物的生物利用度。

Abstract:

OBJECTIVE To prepare genistein-loaded MePEG-PLGA nano-micelle and study its physicochemical properties. To investigate the release characterization in vitro and study the pharmacokinetic characteristics of genistein nano-micelle after single dose in rats. METHODS Genistein nano-micelle was prepared by modified spontaneous emulsification solvent diffusion method, then its physicochemical properties including entrapment efficiency, drug loading, average diameter and Zeta potential were studied. The in vitro release was studied by dynamic dialysis method and the release behavior was fitted with different equations. Put freeze-dried GEN-loaded micelle at 4 ℃ for six months to investigate the changes of the entrapment efficiency and drug loading. The plasma concentrations of Genistein at different time were determined by a developed and validated HPLC method after i.v. administration. The pharmacokinetic parameters were acquired with DAS 2.0 software and analyzed using SPSS 17.0 statistic software. RESULTS The entrapment efficiency, drug loading and average diameter of the prepared nano-micelle were (84.43±2.93)%, (2.63±0.91)% and (63.75±4.12)nm, respectively. The release behavior of the lyophilized Gen nano-micelle was well-fitted to Weibull equation. The entrapment efficiency and drug loading had no significant difference after stored at 4 ℃ for six months. After i.v. administration of Genistein nano-micelle and Genistein emulsion 40 mg·kg^-1, the main pharmacokinetie parameters were as follows: AUC_0-t were (99.46±4.77)mg·L^-1·h and (57.51±1.37)mg·L^-1·h, t_1/2 were (7.48±1.15)h and (4.95±1.15)h, C_max were (16.03±1.20)mg·L^-1 and (16.73±1.10)mg·L^-1, CL were (0.36±0.02)L·h^-1·kg^-1 and (0.67±0.02)L·h^-1·kg^-1. CONCLUSION The genistein nano-micelle was spherical with narrow size distribution and high entrapment efficiency, the genistein nano-micelle possess the properties of sustained release with good stability. Compared with reference injection, the nano-micelle can significantly improve the pharmacokinetic behavior of genistein.