中药浸膏干燥机理及品质形成调控规律研究

The extract is an important intermediate of traditional Chinese medicine (TCM) preparation. The quality of extract directly affects the efficacy of the formulations. The quality and control of the extract are key issues of TCM research. But how to control quality and the drying mechanism of the TCM extract are unclear. Previous studies have shown that, during the falling rate drying stage, extract can form a porous medium structure internally, and the porosity and saturation are key parameters to reflect the structure and basic properties of porous media, and determine the heat mass transfer efficiency of TCM extract, and ultimately affect the quality of traditional Chinese medicine extract (size, mobility, moisture, viscosity, compression, etc.). In this study, five categories of different types of extract as a model, based on the theory of porous media, to use thermodynamic and kinetic methods to explain the mechanism of dried extract of Chinese medicine, to establish quality evaluation system and method of TCM extract from physics, chemistry and thermodynamics multidimensional angle, and study the drying mechanism of the extract, and to explore regulatory policies of high quality of extract. This study can not only provide a scientific basis and theoretical support for solution of common key issues of extract during drying process, but also provide important theoretical and experimental basis for the design of high-quality extract and equipment development.

浸膏是中药制剂的重要中间体，浸膏的品质优劣直接影响到制剂的成型和疗效。浸膏干燥品质形成与调控是中药制剂研究的共性关键问题。但目前有关浸膏干燥机理与品质形成过程尚不清楚。本课题前期研究表明：降速干燥阶段，浸膏内部形成多孔介质结构，孔隙率和饱和度是反映多孔介质结构和基本性能的关键参数，同时决定了中药浸膏降速干燥过程中传热传质的效率，最终影响中药浸膏的形成品质（粒度、流动性、吸湿性、粘性、压缩度等）。为此，本项目选择5类不同类型浸膏为模型，基于多孔介质理论，运用热力学与动力学的方法，阐释中药浸膏的干燥机理，从物理、化学与热力学多维角度建立中药浸膏的品质评价体系与方法，探讨浸膏干燥过程品质形成规律，探求高品质浸膏干燥过程的调控方法。以期为浸膏干燥过程存在的共性关键问题解决提供科学依据与理论支撑，也为高品质浸膏干燥工艺设计及设备开发提供重要理论与实验依据。

研究基本按照原计划执行，一些研究内容稍作调整。（1）选择了高粘性的黄精水提浓缩浸膏、含热敏性的丹参水提醇沉浓缩浸膏、较难干燥的含皂苷的甘草水提浓缩浸膏以及复方中药制剂生脉颗粒水提浓缩浸膏作为模型药进行研究。（2）选择了减压干燥、微波真空干燥、喷雾干燥3种干燥方式进行研究。（3）以不同工艺参数下的干燥速率变化曲线、物料实际受热温度变化曲线，分析中药浸膏的干燥特性，掌握变化及工艺参数影响规律，从工艺角度探讨了“保质、提效”的中药浸膏干燥调控策略。（4）基于能量守恒定律，结合干燥速率与物料内部水蒸气分压建立偏移活化能理论的数学方程，阐释中药浸膏干燥过程中的热质传递特性，为提高中药浸膏干燥效率提供了理论依据。（5）在指纹图谱相似度评价的基础上，采用主成分分析、偏最小二乘法分析研究工艺参数对干膏质量的影响，在此基础上筛选对指纹图谱相似度差异贡献较大的主要差异成分，以此作为工艺评价指标，同时，引入与褐变反应相关的色泽、褐变指数以及5-羟甲基糠醛三个评价指标，明确干燥工艺参数对干膏质量的影响规律。（6）综合干燥特性、偏移活化能理论以及质量评价研究结果，提出“保质、提效”的干燥过程调控策略，并进行实验验证，总结干燥过程调控策略。（7）基于多层感知器与径向基函数建立中药浸膏干燥过程的神经网络预测模型，通过比较分析，确定拟合性能较好的模型，用于控制中药浸膏的干燥过程，提高过程控制水平。