中南药学

目的 以N-异丙基丙烯酰胺(NIPAAm)、壳聚糖(CTS)、丙烯酰胺(AAm)为原料，制备具有温度响应性的载纳豆激酶纳米凝胶(NK@CNA)，考察其处方工艺并对其进行表征，为下一步制备近红外光刺激升温释放药物的纳米粒子奠定基础。方法 利用自由基聚合法制备具有温度敏感性的纳米凝胶粒子(CTS-NIPAAm-co-AAm，CNA)并对其进行表征，单因素考察筛选最优处方工艺；采用BCA试剂盒法进行纳豆激酶含量测定；利用氢键与范德华力制备NK@CNA，通过单因素考察优化载药处方工艺；测定优化后的NK@CNA粒径、电位、形态、包封率和载药量；透析袋法考察NK@CNA体外不同温度下的释药效果；测定其血浆稳定性。结果 制备所得的NK@CNA外观澄清透明，在透射电镜下形态成类球形，粒径为(165.3±3.4)nm，多分散指数(PDI)为0.310±0.030，Zeta电位为(25.1±0.6)mV；纳豆激酶标准曲线为y=1.2663x+0.1132，r=0.9997，且线性、重复性和加样回收率均符合要求；单因素考察优化得到的NK@CNA的处方工艺：载药时间6 h、搅拌速度1000 r/min、NK与载体的质量比为5∶2，所得NK@CNA的平均包封率为(92.98±0.01)%，平均载药量为(1.72±0.001)%，NK@CNA在体外38℃环境下24 h药物累积释放百分比可达92%；血浆稳定性良好。结论 制得的NK@CNA包封率及载药量较高，NK@CNA温度响应性释放药物能力良好，为下一步制备可近红外光刺激升温释放药物的纳米粒子奠定了一定的基础。

Objective To prepare thermoresponsive nanogels loaded with nattokinase (NK) (NK@CNA) with N-isopropylacrylamide (NIPAAm),chitosan (CTS),and acrylamide (AAm) as the raw materials,to determine the formulation process and characterize them,laying the foundation for the preparation of nanoparticles capable of releasing drugs upon near-infrared light stimulation.Methods Thermosensitive nanogel particles (CTS-NIPAAm-co-AAm,CNA) were prepared with radical polymerization and characterized.The BCA reagent kit was used to determine nattokinase content.NK@CNA was prepared with hydrogen bonding and van der Waals forces,and the drug-loading formulation process was optimized by single-factor investigation.The optimized NK@CNA particle size,potential,morphology,encapsulation efficiency,and drug loading were measured.The dialysis bag method was used to determine the drug release effect of NK@CNA at different temperatures in vitro and its plasma stability.Results The prepared NK@CNA was clear and transparent with a quasi-spherical morphology under transmission electron microscopy.The particle size was (165.3±3.4) nm,PDI was 0.310±0.030,and the Zeta potential was (25.1±0.6) mV.The standard curve for nattokinase was y=1.2663x+0.1132,r=0.9997.The linearity,repeatability,and recovery of the sample all met the requirements.The formulation of NK@CNA determined by single-factor investigation included drug loading for 6 h,stirring speed at 1000 r/min,and the mass ratio of NK to carrier of 5∶2.The average encapsulation efficiency of NK@CNA was (92.98±0.01)%,and the average drug loading was (1.72±0.001)%.The drug release rate of NK@CNA at 38℃ in vitro reached 92% within 24 h,with good plasma stability.Conclusion The prepared and optimized NK@CNA has high encapsulation efficiency and drug loading,and shows good temperature-responsive drug release,laying a foundation for the preparation of nanoparticles capable of releasing drugs upon near-infrared light stimulation after temperature elevation.