In Vitro Bioequivalence of Acetylsalicylic Acid and Implications in Public Health

Acetylsalicylic acid is one of the most prescribed medications in the world. It is used for prevention of acute myocardial infarction, colorectal cancer, antipyretic, and as an analgesic. This study aimed to investigate the in vitro bioequivalence of three formulations of acetylsalicylic acid, simulating physiological conditions of the dissolution medium, and analyzing its possible implication for public health. A spectrophotometric method for the quantification of acetylsalicylic acid at 265 nm was used. The dissolution test was performed using a USP apparatus 2 (paddle) with 900 mL of medium at 37 ± 0.5 °C and 75 rpm. At pH 4.5 and 6.8, the three formulations did not meet the criteria of very fast or fast dissolution (85% in ≤ 15 or 30 min, respectively). Generic A has a similarity factor (f₂) of 50 at pH 4.5 and 80.7 at pH 6.8; generic C f₂ values were 31.2 at pH 4.5 and 72.4 at pH 6.8. Generic B did not meet the acceptance range of the similarity factor (50−100) at pH 4.5 and 6.8. For all products tested, the dissolution efficiency was greater than 79%, and the mean dissolution time was 5.5–15.9 min. Based on the in vitro dissolution results, Generic A is bioequivalent with the innovator, whereas generics B and C are not. However, the dissolution profiles of generics A and C are similar to the innovator at pH 6.8, which is the appropriate dissolution medium for this drug.