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.