RESUMEN
OBJECTIVE:To investigate the technological factors that influence the drug release of nitrendipine sustained-release pellets.METHODS:The nitrendipine sustained-release pellets were prepared by extrusion-spheronization technology.By means of in vitro drug release test,the factors that influence the drug release including the amount of the wetting agent and the concentration of ethanol,extrusion speed,spheronisation speed and spheronisation time were investigated to optimize the technological conditions.RESULTS:The amount of the wetting agent and the concentration of ethanol had significant effects on drug release.The optimal concentration of ethanol was less than 35% and the optimal amount of the wetting agent was about 44 mL.Extrusion speed,spheronisation speed and spheronisation time had certain effects on drug release,and their optimal values were 48 r?min-1,1 400 r?min-1 and 5 min,respectively.CONCLUSION:The nitrendipine sustained-release pellets prepared in the above-mentioned technological conditions are up to the standard in drug release velocity.