Modeling drug absorption from enteric-coated granules.

A system-approach-based method is proposed for modeling drug absorption from enteric-coated granules. This method was exemplified using emeric-coated granules of aspirin given to healthy subjects. Based on the results obtained, it can be concluded that absorption of salicylate from the granules can be sufficiently described using a first-order linear model with an absorption rate constant of salicylate similar to that reported for a aqueous solution of aspirin adnunistered orally to healthy subjects. The method proposed in this study may contribute to the working library of modeling techniques in pharmacokinetics since it allows direct modeling of the drug absorption process and estimates the absorption rate constant of a drug when its behavior in the body is significantly influenced by a gastric emptying process, i.e., when the absorption rate constant of the drug cannot be estimated on the basis of its cumulative absorption-time profile.