[Optimize preparation parameters of colon-specific pellets of Angelica Sinensis Radix supercritical fluid extraction with response surface analysis methodology].

To prepare pellets of supercritical fluid extraction (SFE) of Angelica Sinensis Radix by using the ionic crosslinking method, and the drug loading and encapsulation efficiency were used as the index to investigate the multiple factors which may impact the drug loading and encapsulation efficiency. Box-Behnken design and response surface analysis method were then taken to optimize the prescription of pellets and study the coating technology. Through the study on the release of pellets in vitro, an optimal coating technology and prescription of colon-specific pellets of Angelica Sinensis Radix SFE were selected and their colon targeting was evaluated. The optimal preparation parameters of pellets were determined as follows： 3% pectin; 4∶1 for pectin/lecithin; 4∶5 for pectin/SFE of Angelica Sinensis Radix; 4% zinc acetate solution as crosslinking agent, blending temperature 35 ℃, crosslinking temperature 35 ℃, crosslinking time 30 min; coating technology： coating material Eudragit FS 30D, 1.5% triethyl citrate and polyoxyethylene sorbitan monooleate（tween-80）, 1.2% monostearin and 15% coating weight gained. The colon-specific pellets of Angelica Sinensis Radix SFE prepared with optimized conditions were almost not released in simulated gastric fluid in 2 h, released less than 20% in simulated intestine fluid in 4 h, and released more than 90% in simulated colon fluid in 6 h, indicating that the colon-specific pellets of Angelica Sinensis Radix SFE had an excellent colon targeting property.