Abstract: The bioavailability of the three formulations of aspirin tablets, Al-aspirin, bufferedand unbuffered tablet, was evaluated with 12 healthy volunteers (9 male, 3 female). Observed data from single. oral dose were compared with those calculated and the results indicated that the differences between the three formulations were significant. The buffered aspirin tablet was better than the others. The faster rate of dissolution associated with buffered tablet resulted in earlier peak time and higher peak concentration. The in vitro dissolution rate, T_50%, was related to the peak concentration and the area under the blood level-time curve.