BIORELEVANT MEDIA.An analytical method by liquid chromatography has been proposed and validated to study the apparent solubility of ibuprofen in biorelevant dissolution media.The main properties of the studied media were pH values of 5.0 and 6.5 and the presence or absence of some natural surfactant agents.The parameters evaluated were specificity, linearity, precision, accuracy, and detection and quantification limits, as well as the drug stability under the analysis conditions.The developed method was useful to determine the apparent solubility of this drug as a function of temperature and surfactants concentration to demonstrate the validity of the Biopharmaceutics Classification System.