Preparation and stability investigation of tamsulosin hydrochloride sustained release pellets containing acrylic resin polymers with two different techniques

The objective of this study was to prepare tamsulosin hydrochloride-sustained release（TSH-SR）pellets which showed good release stability with frame-controlled method.TSH was added to Eudragit;NE30D and Eudragit;L30D-55 polymers to form drug-loaded inner core.Afterwards,enteric Eudragit;L30D-55 polymer was modified on the surface of it to the final product.Dissolution studies showed that TSH-SR pellets were more stable during the coating process,different curing temperatures and storage conditions compared with TSH pellets produced by film-controlled technique.Appearances and glass transition temperatures（Tgs）of free films and surface morphologies observed by scanning electron microscopy（SEM）of blank sustained release pellets prepared by different ratios of Eudragit;NE30D and Eudragit;L30D-55 further indicated that temperature and relative humidity（RH）were the key factors when Eudragit;NE30D blended with Eudragit;L30D-55 were applied to sustained/controlled release preparations.In addition,SEM identified the surface morphologies of TSH-SR pellets before and after dissolution,which showed intact surface structure and great correlation with release curve respectively.