[Preparation and in vivo evaluation of pH and time dependent Yuchangning tablets for colon-specific delivery].

Objective: Taking Chinese compound medicine Yuchangning as a research model, prepared the pH and time dependent Yuchangning tablets for colon-specific delivery (PT-YT-CSD), and evaluated the releasing property in vitro.

Method: The coating prescription is filtered by the release extent of matrine and oxymatrine in vitro and the wicking rate of the tablet, which including the category and proportion of film forming agent and porogen, the sort and dosage of fluidizing agent, the increment of weight after coating and so on. The releasing property of the preparation is evaluated by the dissolution tests in vitro through measuring the content of matrine and oxymatrine content.

Result: The preparation method of the PYTCSD: After prepared plain tablets, the 95% alcoholic solution of EC and Eudragit II are mixed in a 7:3 EC: Eudragit II ratio and then added in DEP up to 10% of the coating amount, reduced the alcohol concentration to 4% by diluting with ethonal. Tablet was coated by the alcohol solution and the weight of the plain tablet was increased by 3%. The dissolution tests in vitro indicated that matrine and oxymatrine were not dissolved in the simulated gastric juice after 2 h. The accumulative quantities of matrine and oxymatrine were less than 10% in the simulated intestinal juice after 4 h. The quantities of matrine and oxymatrine are 75.7% and 76.8% in the simulated colon juice after 1 h.

Conclusion: The PYTCSD was prepared and the preparation could fulfil the aim of delivering in the specific colon in vitro.