This paper presents results of a pharmacokinetics study concerning pentoxifylline and its main metabolites after administration of extended release formulation of Trental 400 mg and correlation of this pharmacokinetics with in vitro dissolution test results of parent drug. In order to establish most relevant in vitro test, dissolution was performed in different experimental conditions (stirring rate and dissolution medium). Correlation was linear and very good. Generalization of correlation to rate of appearance of metabolites in plasma proved that this process could be well correlated with dissolution. Most relevant test was finally found to be the release in water medium, in conditions of a high stirring rate - 100 rpm.
Keywords: apparent absorption; biorelevant test; dissolution; in vivo–in vitro correlations; pentoxifylline and its principal metabolites.