Characterization and utilization of acid-modified cross-linked Tapioca starch in pharmaceutical tablets

Tapioca starch was cross-linked in the presence of alkaline sodium trimetaphosphate solution. The cross-linked tapioca starch was hydrolyzed by 6% (w/v) HCl solution at room temperature for 192 h. The final product was dried by centrifugal spray dryer to obtain agglomerated acid-modified cross-linked tapioca starch. Spray-dried native tapioca starch, cross-linked tapioca starch and acid-modified tapioca starch were also studied parallel with that of acid-modified cross-linked tapioca starch. It was found that cross-linking didn't increase the relative crystallinity or the melting enthalpy of tapioca starch. Compression of both native and cross-linked tapioca starches gave tablets with a very low crushing strength. Acid hydrolysis introduced to remove the amorphous regions in order to increase the crystallinity of both types of starches, resulting in tablets with a higher crushing strength. In this respect tablets prepared from acid-modified cross-linked tapioca starch were better than those prepared from acid-modified tapioca starch. (C) 2003 Elsevier Science Ltd. All rights reserved.