OBJECTIVETo prepare gastric floating sustained-release formulation of Tripterygium wilfordii by using multiparticulate time-controlled release technology.

METHODThe intra-gastric floating blank-pellets were made by extrusion-spheronization method with 10% MCC as diluent and 90% cetylalcohol as floating assistant. The drug-loaded pellets were prepared in a fluid-bed coater with 1% HPMC, 0.5% SDS and extraction of T. wilfordii as coating solution. The gastric floating time-controlled release pellets were prepared with 3% L-HPC, 1% HPMC and 1% SDS as the inner swelling layer and ethylcellulose aqueous dispersion as the outer controlled layer. Finally, gastric floating sustained-release capsules of T. wilfordii were developed by encapsulating the five kinds of coated pellets whose coating load were 0%, 8%, 12%, 15% and 22% at equivalent ratio in hard gelatin capsules.

RESULTAfter formulation and coating load of swelling layer was fixed, the coated pellets would release active compositions in the different time expectably through regulating coating level of controlled layer. Several kinds of coated pellets whose controlled layer had different coating load were mixed and encapsulated into gastric floating sustained-release capsules of T. wilfordii. The capsules could float immediately in the dissolution medium and the floating rate of pellets was more than 80% in 8 h. The various kinds of coated pellets could release active compositions in accordance with time and show a characteristic of sustained-releasing as a whole.

CONCLUSIONThe gastric floating sustained-release capsules of T. wilfordii prepared by using multiparticulate time-controlled release technology have effective floating behavior and sustained release characteristics.