Abstract: To separate and purify andrographolide by supercritical carbon dioxide extraction and crystallization with 30% andrographolide material. The single factor method to investigate the effect of technology parameters: pressure, temperature and time on purity of andrographolide was adopted. The result was that there was synchronous crystallization in separation and purity of andrographolide by supercritical CO2 extraction, and gradie of appeared distributin on the crystal board. When we selected the parameters pressure 20MPa, temperature 55℃, and time of crystallization 90min, the purity of andrographolide was more than 80%.

Key words: supercritical carbon dioxide, extraction, crystallization, gradient distribution, andrographolide