A comparative study of glycerin fatty acid ester and magnesium stearate on the dissolution of acetaminophen tablets using the analysis of available surface area.

To study the effect of glycerin fatty acid ester (Poem TR-FB) concentrations on the dissolution rate of acetaminophen (APAP), the dissolution and disintegration behaviors of APAP tablets formulated using various lubricants were examined. The change over time in the available surface area of APAP (S(t)), which is in direct contact with solvent, was also analyzed using these dissolution data. In the dissolution tests, a retarded dissolution of APAP was not observed with TR-FB, whereas magnesium stearate (Mg-St), which is widely used as a lubricant, retarded the dissolution. However, no significant difference in the disintegration time between the two lubricants was observed. With regard to the time course of the S(t), Mg-St at 0.1% gave a maximum surface area value at 9.19 min (peak time); however, the profiles for APAP with Mg-St at greater than 0.5% showed downward curvature indicating a gradual decrease in surface area over time. Conversely, with TR-FB, even when its concentration was increased, the S(t) profile for APAP had a maximum value that was more than twice that of APAP with that of 0.5-3.0% of Mg-St. Scanning electron microscopy (SEM) observations showed that the differences in the dissolution rate and S(t) patterns between Mg-St and TR-FB could be explained by differences in extensibility deriving from their morphology. Therefore, it was concluded that TR-FB does not cause retardation of drug dissolution and may prove to be a superior alternative lubricant to Mg-St.