Objective:To evaluate the release characteristics of compound berberine hydrochloride colon specific tablets in rats. Method:The rats were administrated orally with the colon-specific tablets of diameter 3 mm and berberine hydrochloride (BH) suspension respectively. After administration

the rat's plasma and gastrointestinal tissues were collected at different time points within 22 h. The berberine in biosamples was determined by HPLC

using palmatine as internal standard. Drug delivery index (DDI) was calculated. Result:BH in plasma and gastrointestinal tissues showed good linear relationship in the range of 0.02-0.40 mg·L-1 (r>0.998) and 0.05-10.0 mg·L-1 (r>0.999) respectively. The release of BH in tablets mainly distributed in rat's caecum and colon and showed an obvious lag time. The value of Cmaxand AUC0-22 h in rat's colon were 3.1 times and 3.6 times of BH suspension group respectively. The DDI of the tablets was 0.00

0.23

1.17

2.36

8.55 in the rats' gastric

proximal and distal small intestinal

caecal

colonic tissue

respectively. Conclusion:The compound berberine hydrochloride tablet is a carrier for targeting the drug to the colon.