Pregelatinized starches were produced from hydrochloric acid treated: corn, glutinous rice and tapioca starch using double drum dryer. The reaction of acid treated conditions i.e. hydrochloric acid concentration, temperature and time of treatment were varied to obtain the acid modified starches having two lower levels of viscosity when compared with their native forms. It was found that the higher levels of treatment conditions, the lower viscosity of acid treated starches were attained. However, when both levels of acid treated were prepared into pregelatinized starches, their viscosities became similar, except that of glutionous rice starches. Pregelatinized starches obtained were evaluated in term of their powder properties, granule properties and tabletting characteristics when they were used as filler/binder in acetaminophen formulations comparing with three of commercial pregelatinized starches (Era-Gel, National 1551 and Starch 1500). In the study of powder properties, it was found that the physical properties of acid treated corn, glutinous rice and tapioca starch at both levels of viscosity appeared virtually unchanged from their native starches while the pregelatinized of all starches exhibited the entire differences. All pregelatinized starches obtained were completely gelatinized and there were no changes of chemical functional groups during their processing. The swelling capacity and amount of soluble substances of pregelatinized starches obtained were increased, also the flowability of the powders. When all pregelatinized starches prepared were evaluated as filler/binder in acetaminophen tablets, it was found that the pregelatinized native corn starches, pregelatinized starch of both levels of acid treated corn starches and tapioca starches exhibited the satisfactory fillers/binders in acetaminophen tablets in term of physical properties, disintegration (within 0.78-5.23 mins) and dissolution time (T80% between 2.92-7.00 mins), while the tablets contained pregelatinized of native tapioca starch, pregelatinized of native glutinous rice starch and pregelatinized starch of both levels of acid treated glutinous rice starches gave good tablets physical properties but having very slow disintegration time (>60.00 mins)
