The Process Of Supercritical Carbon Dioxide Extraction And Purification Of Artemisinin

There was artemisinin in Artemisia annua L, which was the active ingredient of antimalarial with great market value. It was important that studying the process of extracting and refining the artemisinin from crude materials with abundant Artemisia annua L in our country. It was summarized that solubility of related matters in supercritical carbon dioxide, the application and development of supercritical carbon dioxide extraction and the actuality of the extracting and refining the artemisinin. It was whole studied the process of supercritical carbon dioxide extraction of the artemisinin from Artemisia annua L, the Column chromatography and crystallization refining the artemisinin subsequently.Based on the present process of extracting artemisinin with supercritical carbon dioxide, it was optimized that the condition of the extraction and the separate for high purity of artemisinin. The optimal condition was that temperature 40℃ and pressure 18 MPa of extraction cell, temperature 60℃ and pressure 14 MPa of separate cell I , temperature 50 ℃ and pressure 4-5 MPa of separate cell II , particle size 60 to 80 meshes of raw material, CO₂ flow rate 1 kg of CO₂ per kg , extraction time of 4 h. It was improved that the purity of artemisinin in the separate cell II with the mild extraction condition and the separate effect of separate cell I .It was acquired that the purity of artemisinin in the separate cell I was 8%-9%, the purity of artemisinin in the separate cell II was about 20%,and the recovery was about 90%. After the supercritical carbon dioxide extraction, the purity was improved from 0.6% to about 20%, and the extraction time was short, the extraction condition was mild.Because of the low purity of artemisinin after the supercritical carbon dioxide extraction, it was thoroughly investigated that the condition of Silica gel Column chromatography for high purity of artemisinin to meet the demand of the market. First, two mobile phases were compared with thin-layer chromatography. The appropriate mobile phase was decided with Silica gel Column chromatography. With the the appropriate mobile phase and stationary phase, it was investigated that differentconditions of Silica gel Column chromatography such as flow rate and sample load for the optimal one.And with optimal conditions of Silica gel Column chromatography, the recovery of Silica gel Column was thoroughly investigated with the same condition of Silica gel Column chromatography. It was confirmed that the best mobile phase was n-hexane:ether =80:20 (by volume), the Silica gel stationary phase was 100-200 meshes. The optimal operation conditions were flow rate 0.5 cm ? min'1, sample load 18.9 mg ? mL"1. The silica gel column might be regenerated by 2 bed volumes of methanol. The purity of artemisinin can be improved from 15% to more than 70% after purification, and the recovery was 90%.Based on the literature, the crystallization of the product of Silica gel Column chromatography was studied. Two solvents and their volume were compared for crystallization. 70% ethanol was chosen as the best solvent and 15 times volume for crystallization. Then the purity of artemisinin was improved from 61.2% to about 99% after crystallization.By the process of supercritical carbon dioxide extraction. Silica gel Column chromatography and crystallization, the artemisinin was well extracted and refined. The purity of artemisinin was improved from 0.6% of Artemisia annua L to 99%. The whole process provided an appropriate technique for the extraction and purification of artemisinin.