Objective: To optimize ultrafine pulverization process of Codonopsis Radix and investigate its in vitro dissolution. Method: Taking extraction amount of lobetyolin as index

orthogonal test was adopted to optimize ultrafine pulverization process with powder consumption

preliminary powder fineness and pulverization time as factors.HPLC was employed to determine the content of lobetyolin with mobile phase of acetonitrile-water (20:80) and detection wavelength of 268 nm.Dissolution was determined by Paddle-shaped mixing method

the content of lobetyolin in stripping liquid at different times from ultrafine powder and ordinary powder was compared. Result: Optimal ultrafine pulverization technology was as follows:preliminary powder fineness 65 mesh

powder consumption 1 000 g

pulverization time 40 minutes;Average extraction amount of lobetyolin was 3.95 mg·g-1 with RSD of 2.85%.Compared with ordinary powder

the content of lobetyolin in stripping liquid from ultrafine powder increased by 35%

dissolution of ultrafine powder in 30 min was up to 80%

while it was 40% in 120 min for ordinary powder. Conclusion: This optimized technology was stable and feasible

dissolution rate of lobetyolin in ultrafine powder was much larger than ordinary powder.