溶剂流动方式对药物提取过程的影响

以大黄为实验材料 ,利用半连续提取设备 ,分别采用简单提取和循环提取的方式 ,研究了溶剂流速对提取率和提取液浓度的影响。结果表明简单提取的速度快 ,极限提取率高 ,提取液浓度在初期很高 ,并随提取率增加而下降 ;循环提取溶剂用量和提取液浓度易控制 ,收率受级平衡限制而较低 ;适当增大溶剂流速可缩短提取时间 ,但会增加前者的溶剂消耗 ;在简单提取中引入回流对后期的提取有一定促进作用 ,回流的时间和回流强度值得研究。将简单提取和循环提取适当组合能够在保证效率的基础上使收率和提取液浓度有较大提高。

Influence of solvent flow on herbal extraction

Effects of solvent flow rate on extraction ratio and extract concentration in the simple extraction and circulation extraction were studied by using semi-continuous extraction equipment with rhubarb as experimental material.Results show that the simple extraction is quicker,it has higher extraction ratio of the extreme limit and higher extract concentration at the initial stage which will decrease with the increase of extraction ratio.The yield is lower due to limitation of equilibrium,solvent consuming and extract concentration can be controlled easily.Increasing solvent flow rate in a proper way can cut extraction time,but more solvent is needed for the simple extraction.Reflux introduced in the simple extraction can make some improvement for later extraction,while time and intension of reflux are pivotal and worthy of study.Proper combination of simple extraction and circulation extraction can increase yield and extract concentration simultaneously on the basis of assurance efficiency.