Objective: To prepare colon-targetting tablets containing total alkaloids of Sophora alopecuroides and evaluate sophoridine release profiles in vitro. Method: Wet granulation technique was employed to prepare guar-based matrix tablets

optimizing the formula by drug release studies in successive different mimicking media in vitro. Result: These results indicated that the granulations of various formulations showed good flow characteristics

hence

good compressibility. The granulation of formulation A was more fragile

with the increase of the amount of guar

while the granulations of formulation B-D became less fragile. At compression force of 25 kN

the hardness of formulation C was maximal

probably due to better proportion of the fine fraction and coarse fraction of the granula. The guar-based matrix tablets released 13.5% to 25.6% of sophoridine in the first 6 h

and released rapidly 55.4%~75.1% in SCF for the first 6 h. Bilayer matrix tablet met required physical properties

its initial release was lagging. Within first 6 h

there was only 6.78% released from matrix tablet

and almost no drug released within 2 h

and the guar matrix completely dissolved in 24 h. Dissolution data of various formulations was fit best to Higuichi model

and its release mechanism belonged to bulk erosion. Conclusion: Total alkaloids of S. alopecuroides colon-site targetting tablets could deliver total alkaloids of S. alopecuroides to desire site and its preparation is reasonable.