Preparation of Yiguanjian time-controlled release pellets and their in vitro release characterization

Objective To prepare Yiguanjian(traditional Chinese medicines) time-controlled release pellets and investigate drug release behavior in vitro. Method Yiguanjian pellets were prepared by extrusion-spheronization method after refining the extracted material medica. Thereafter, using water swelling material as the inner swelling layer and ethylcellulose aqueous dispersion(Surelease) as the outer controlled layer, Yiguanjian sustained-release pellets were prepared in a fluid-bed coater. Factors influencing the in vitro drug release was investigated. Results Keeping low-substituted hydroxypropyl cellulose(L-HPC) as the coating material of the inner swelling layer with a weight increase of 20 %, three different kinds of Yiguanjian sustained release pellets were prepared by keeping the weight ratio of the outer Surelease coating membrane at 0 %, 20 % and 24 %, respectively. Yiguanjian sustained-release capsules were developed by mixing the above three kinds of coated pellets at an equivalent ratio. No significant difference was found in the in vitro release behavior of catalpol and ferulic acid from Yiguanjian sustained-release pellets, with f2 value of 78.2, with apparent sustained release properties. Conclusion Various components could be released synchronously from Yiguanjian sustained-release pellets in a sustained manner. This comforms to the theory of traditional Chinese medicine.