control of physicochemical properties of different manufacturers of Iranian acetyl salicylic acid(ASA) tablets

the physicochemical properties of Iranian acetyl salicylic acid(ASA) tablets,including the products of 10 manufacturers with 14 products,from each 3 batches,totally 42 products have been studied.the properties under investigation are hardness,friability percintage,humidity percentage,free salicylic acid,content uniformity,amount of ASA disintegration time,and released percentage.the results indicate that there are significant differences between different manufacturees of chewable ASA tablets(100 mg) with respect to humidity percentage and disintegration time(p<0.001).the 325 mg tablets of different manufacturers also show significant differences regarding to all parameters(p<0.005), expect friability and hardness.however the uncoated 500mg tablets are not significantly different (p<0.05),except for hardness,humidity and amount of active ingredient.although microcoated ASA tablets have no differences in friability percentage (p<0.05) all tablets are significantly different with respect to humidity,disintegration time,amount of active ingredient and released percentage (p<0.05).