The Establishment Of SPE-HPLC Method And The Research On The Pretreatment Techniques Of Taxol

Paclitaxel (taxol) is an important anticancer natural product which was isolated from the yew tree. it has been permitted to treat ovarian and breast cancer by many countries. So far. Paclitaxel mostly depended on isolating from yew tree. Its production technics consist of four parts. pretreatment. chromatographic isolation, back-treatment and chemical translation. As a part of studies of production of taxol. the role of pretreatment was to eliminate more polar and apolar impurity. it not only reduce the following chromatography's burden, but also play or improve its high selective ability. In this paper, we desired to develop a pretreatment method suitable for the large-scale screening of Taxus crude extract, laid a foundation for the whole production work.In this paper, the comprehensive design of studying overall pretreatment methods, "compared between New and Traditional methods", was put forward for the first time. Firstly, studied objects were selected, including two new techniques. H-Y liquid-liquid extraction and resin chromatography. and two traditional techniques, chloroform extraction and acidic-basic precipitation. The next step was to decide the concrete evaluating index and develop related analytical methods. Finally, results of each index were analyzed and an ideal pretreatment technique was selected.The indeces selected in the paper were impurity elimination rate, decoloration rate and paclitaxel recovery. In addition, weight, electrical conductance(EC). UV. TLC and HPLC were selected as related analytical methods, especially. HPLC method was emphasized. Prior to analysis for taxanes of different polarity by HPLC. the neutral Al₂O₃ solid phase extraction (SPE) was used to screen of the crude extract, furthermore, the chromatographic conditions of SPE was researched generally. In order to avoid a problem with the dissolving of the crude encountered as adding sample of SPE, it was decided to use methanolto dissolve the crude, added to the column and evaporated to dryness in vacuum-desiccator. To our knowledge there is presently no published such method, which not only solve the solubility problem, but also release methanol decreasing absorption and isolation ability of AItOv The results indicated that the neutral Ai;Ch SPE can eliminate a great deal of impurity, paclitaxel was enriched effectively and its recovery was over 90%. purity was improved from 0.7% to 25%.It was found that the impurity elimination rate of H-Y liquid-liquid extraction was the highest, exceeding 85%, next is resin chromatography. acidic-basic precipitation was most badly. There were same trends for decoloration rate and paclitaxel recover}'. During the impurity screening by H-Y liquid-liquid extraction and resin chromatography. paclitaxel was almost fully recovered. According to TLC and HPLC results, impurity eliminated by H-Y liquid-liquid extraction and resin chromatography was more polar substance. In our research. H-Y liquid-liquid extraction can completely eliminate the more polar impurity, there was still much more polar impurity which didn't spread on the origin of TLC plate for other techniques.In conclusion. H-Y liquid-liquid extraction was the best one among the four pretreatment techniques, this method appears to be suitable for the large-scale screening of crude samples because of its simplicity and low use of organic solvents and especially its high productivity.