Comparative bioavailability of three batches of four commercial acetaminophen tablets.

The aim of this investigation is to evaluate four brands of acetaminophen tablets and three batches of each brand for their in vitro properties and in vivo bioavailabilities using urinary excretion data. All batches dissolved at least 80% of their acetaminophen content within 30 minutes. The differences between the dissolution rates of the batches were not found statistically significant except the batches of brand C. With respect to their dissolution rates, the brands have the following order: A less than B less than C less than D. Statistical analysis of the percent bioavailabilities and the elimination rate constants showed that there was no significant difference between brands and or between the batches. The percent excreted in the first three hours was found to be significantly different between the solution and tablet A, between tablet A and tablet C, and between Tablet A and Tablet D.