Application of high-speed counter current chromatography in extraction and separation of alkaloids in natural products / 中国中药杂志

Alkaloids, widespread in plants, have a series of pharmacological activities and have been widely used to treat various diseases. Because alkaloids are usually presented in multicomponent mixtures and are deeply low in content, they are very difficult to extract and separate by traditional methods. High-speed counter current chromatography(HSCCC) is a kind of liquid-liquid chromatography without solid support phase, which has the advantages of large injection volume, low cost, and no irreversible adsorption. Compared with the traditional methods of extraction and separation of alkaloids, HSCCC can ensure the separation of many different alkaloids at one time, with a high recovery and large amount. In this paper, the advantages and disadvantages of HSCCC compared with traditional separation methods were discussed and the solvent system and elution mode of HSCCC used to separate alkaloids in recent years were summarized by referring to the relevant literature to provide some references for the separation of alkaloids by HSCCC.

Counter-current flow in artificial kidneys

The he parameters controlling the design and function of artificial 1 kidney systems, namely surface area of the transfer medium, [membrane], its permeability as well as operating conditions such as the rate of flow of both the blood and dialysate were correlated, The obtained correlation provides a means For calculating the artificial kidney performance [dialysance] in terms of blood flow rat blood to dialysate flow rate ratio, membrane surface area and membrane permeability : D= Q B[1- [1-k] / [e[1-k] PA / Q[B-k]] < 1 Considering the equation commonly used for calculating membrane permeability i.e. Renkin formula it is worth noting that it can only be applied for specific cases where blood to dialysate flow rates are extremely low and it may be considered as a specific case of the predicted equation