【作者】 陈慧娟；

【导师】 李小芳；

【作者基本信息】 成都中医药大学 ， 中药学， 2022， 硕士

【摘要】 槲皮素（Quercetin,QUE）因具有强大的抗氧化活性,对多种疾病起到预防和治疗的作用,主要包括癌症、代谢性疾病、心血管疾病等。然而,QUE的临床疗效经常受其水溶性差和生物利用度低的限制。纳米混悬剂被认为是一种有前景的改善难溶性药物溶解度和生物利用度的策略。在本研究中,QUE被制备成纳米混悬剂,以改善其溶出行为和生物利用度,从而克服它在临床应用方面的局限性。同时,本研究开发和利用了一种天然来源的新型稳定剂——绞股蓝皂苷,对其作为纳米混悬剂的天然稳定剂替代传统合成稳定剂的可行性进行了评估。使用高速剪切-高压均质法来制备绞股蓝皂苷稳定的槲皮素纳米混悬剂（Quercetin nanosuspensions,QUE-NS）。通过单因素试验和响应面法优化了QUE-NS的处方和制备工艺,获得的最佳条件如下:QUE浓度为0.8 mg·m L^-1、绞股蓝皂苷浓度为1.5 mg·m L^-1、剪切转速为13000 r·min^-1、剪切时间为2 min、均质压力为100 MPa、均质次数为12次。在此工艺条件下,制备的QUE-NS为黄色混悬液,平均粒径为（461.9±2.4）nm,多分散指数（Polydispersity index,PDI）为0.059±0.016。此外,与纳米混悬剂的常用稳定剂相比,由绞股蓝皂苷稳定的QUE-NS的平均粒径和PDI最小,这表明绞股蓝皂苷具有优异的稳定效果。为了探索基于绞股蓝皂苷的纳米混悬剂的稳定性,考察了pH、离子强度、绞股蓝皂苷浓度以及储存条件对QUE-NS的影响。结果显示,使用绞股蓝皂苷制备的纳米混悬剂在6到8的pH范围内表现出良好的稳定性,而在酸性（pH3-5）条件和盐存在的情况下出现不稳定现象。绞股蓝皂苷的浓度对QUE-NS的Zeta电位影响不大。此外,QUE-NS在两种不同的储存条件下,30天内的平均粒径和PDI均无明显变化,说明该制剂可以在一个月内保持高度的稳定性。采用冷冻干燥法将QUE-NS转变成固体形式的粉末,不但有利于后续的制剂研发,还能提高患者的依从性。根据单因素试验的结果选择乳糖作为冻干保护剂。当使用5%（w/v）的乳糖作为冻干保护剂时,QUE-NS冻干粉在水中复溶后的平均粒径和PDI变化最小,这表明乳糖在5%（w/v）的浓度下达到最佳保护性能并使QUE-NS冻干粉保持良好的再分散性。将槲皮素制备成QUE-NS之后,其物理外观明显改变。使用扫描电子显微镜和透射电子显微镜观察到槲皮素原料药为微米级的棒状晶体,而QUE-NS中的药物颗粒呈块状,且粒径小于500 nm。粉末X射线衍射和傅里叶变换红外光谱的结果表明在生产过程中QUE的化学结构和结晶性质没有发生明显变化。影响因素试验的结果显示,QUE-NS冻干粉在高湿条件下较不稳定,出现轻微的颜色加深和吸湿结块,而在高温和光照条件下相对稳定。体外溶出特性的研究结果显示,与QUE原料药相比,QUE-NS冻干粉的饱和溶解度和体外溶出度均显著提高,这主要归因于粒径的减少导致更大的表面积。同时,溶出度较高的QUE-NS冻干粉比QUE原料药具有更强的体外抗氧化活性。上述结果表明,将QUE制备成纳米混悬剂之后,可以改善QUE的溶解度和溶出速度,从而提高其在体外的抗氧化活性。更多还原

【Abstract】 Quercetin（QUE）has strong antioxidant activity,and is commonly used to prevent and treat many diseases,including cancer,metabolic diseases,and cardiovascular diseases.However,the clinical efficacy of QUE is often limited by its poor water solubility and low bioavailability.Nanosuspensions are considered as a promising strategy to improve the solubility and bioavailability of poorly water-soluble drugs.In this study,QUE was prepared as the nanosuspension to improve its dissolution behavior and bioavailability,thereby overcoming its limitations in clinical applications.More importantly,this study developed and utilized a novel stabilizer from natural origin,gypenosides,and evaluated its feasibility as a natural stabilizer of nanosuspensions to replace traditional synthetic stabilizers.Quercetin nanosuspensions（QUE-NS）stabilized by gypenosides were prepared by high-speed shearing and high-pressure homogenization.The formulation and preparation process of QUE-NS were optimized by single factor experiment and response surface methodology.The optimal conditions obtained were as follows:QUE concentration was 0.8 mg·m L^-1,gypenosides concentration was 1.5 mg·m L^-1,shear rate was 13000 r·min^-1,shear time was 2 min,homogenization pressure was 100 MPa,and homogenization times was 12 times.Under these conditions,the prepared QUE-NS were yellow suspensions with mean particle size of（461.9±2.4）nm and polydispersity index（PDI）of 0.059±0.016.In addition,compared with the commonly used stabilizers for nanosuspensions,the mean particle size and PDI of QUE-NS stabilized by gypenosides were the smallest,indicating that the stabilizing efficiency of gypenosides was superior.To explore the stability of gypenosides-based nanosuspensions,the effects of pH,ionic strength,gypenosides concentration,and storage conditions on the stability of QUE-NS were investigated.The results demonstrated that nanosuspensions stabilized by gypenosides exhibited good stability in the pH range of 6 to 8,but instability was prone to occur in acidic conditions（pH3-5）and the presence of salt.The concentration of gypenosides had little effect on the Zeta potential of QUE-NS.Moreover,QUE-NS showed no significant change in particle size and PDI within 30 days under two different storage conditions,indicating that the formulation could maintain high stability for one month.Converting QUE-NS into powders in solid form by freeze-drying not only facilitates subsequent formulation development,but also improves patient compliance.According to the results of single factor experiment,lactose was selected as the lyoprotectant.When 5%（w/v）lactose was used as the lyoprotectant,the change in mean particle size and PDI of QUE-NS lyophilized powder after reconstitution in water was minimal,indicating that lactose achieved the best protective performance at the concentration of 5%（w/v）,and made QUE-NS lyophilized powder maintain excellent redispersibility.After quercetin was prepared into QUE-NS,its physical appearance changed significantly.Using scanning electron microscopy and transmission electron microscopy,it was observed that the QUE coarse powder was micron-sized rod-like crystals,while the drug particles in QUE-NS presented a lumpy morphology,and the particle size was less than 500 nm.The results of powder X-ray diffraction and fourier-transform infrared spectroscopy indicated that there was no significant difference in the chemical structure and crystal state of QUE during the production process.The test results of influencing factors showed that QUE-NS lyophilized powder was unstable under high humidity conditions,with slight color deepening and moisture absorption,while it was relatively stable under high temperature and light conditions.In vitro dissolution characteristics of QUE-NS was investigated.The results indicated that compared with QUE coarse powder,the saturated solubility and in vitro dissolution of QUE in lyophilized powders were significantly increased,which was mainly due to the reduction of particle size resulting in larger surface area.And QUE-NS lyophilized powder with higher dissolution showed stronger in vitro antioxidant activity than QUE coarse powder.The above results showed that the solubility and dissolution rate of QUE could be improved after preparing QUE into the nanosuspension,thereby enhancing its antioxidant activity in vitro.更多还原