基于水动力学尺寸调控中药多组分喷干粉的表面组成:以多糖和蛋白二元体系为例

目的探讨水动力学尺寸(水合粒径)与中药多组分喷干粉表面成分分布的关系,以实现表面组分径向有序分布的调控。方法选取具有特定相对分子质量的溶菌酶与葡聚糖代替中药提取液中含量丰富的蛋白和多糖2种高分子物质,制备不同含量混合物溶液。采用激光光散射法测定其溶液状态下的水合粒径;喷雾干燥后采用X射线光电子能谱测定喷干粉表面元素,并将两者进行相关性分析。继而调节溶液环境,观察水合粒径与表面元素变化情况。最后测定粉体稳定性、吸湿性及含水量等性质。结果溶液环境导致物质粒径发生变化,其中溶菌酶的水动力学尺寸随溶液离子强度或pH值的增加而增加,葡聚糖的水动力学尺寸随溶液离子强度或pH值的增加而减小。X射线光电子能谱分析表明混合物喷干粉表面均存在蛋白表面富集现象,其中高离子强度或高pH值下喷干粉的蛋白表面富集程度更高,这与高离子强度或高pH值时溶菌酶水合粒径尺寸增加的趋势是一致的。颗粒性能测试实验表明对于以水为溶剂的葡聚糖-溶菌酶二元喷干粉,溶菌酶的加入使得混合物的吸湿性降低、稳定性提高,另外提高溶液离子强度或者pH值则使喷干粉稳定性进一步提高。结论水动力学尺寸是影响蛋白富集于喷干粉表面的主要因素,且由于低吸湿性蛋白在喷干粉表面的富集,导致混合物吸湿性降低,有效提高其物理稳定性。

Controlling surface composition of multi-component spray-dried powder of traditional Chinese medicine based on hydrodynamic size: Taking binary system of polysaccharide and protein as an example

Objective To explore the relationship between the hydrodynamic size (hydrated particle size) and the surface composition distribution of the multi-component spray-dried powder of traditional Chinese medicine, in order to realize the regulation of the radial orderly distribution of the surface components. Methods The lysozyme and dextran with specific molecular weight was selected to replace the two high molecular substances of protein and polysaccharide which were rich in Chinese medicine extract to prepare different mixtures. The laser light scattering method was used to determine the hydrated particle size in the solution state. After spray drying, X-ray photoelectron spectroscopy was used to determine the surface elements of the sprayed powder, and the correlation between them was analyzed. Then the solution environment was adjusted to observe the changes in hydrated particle size and surface elements. Finally, the properties of powder stability, hygroscopicity, and water content were measured. Results Different solution environments could cause changes in the particle size of the materials, in which the hydrodynamic size of lysozyme increased with the increase of ionic strength or pH value in the solution, while the hydrodynamic size of dextran decreased with the increase of ionic strength or pH value in the solution. X-ray photoelectron spectroscopy (XPS) analysis showed that there was protein enrichment on the surface of the powder, and the protein enrichment degree was higher at high ionic strength or high pH value, which was consistent with the increasing trend of lysozyme hydrated particle size at high ionic strength or high pH value. The particle performance test showed that for the dextran-lysozyme binary spray-dried powder with water as the solvent, the addition of lysozyme decreased the hygroscopicity and improved the stability of the mixture. Furthermore, the stability of the spray-dried powder was further improved by increasing the ionic strength or pH of the solution. Conclusion The hydrodynamic size is the main factor affecting the concentration of protein on the surface of the sprayed powder. Due to the enrichment of low-hygroscopic protein on the surface of the spray-dried powder, the hygroscopicity of the mixture is reduced and the physical stability is improved.