Modeling the solubility of oxaprozin and irbesartan in biorelevant complex solutions based on a combination of pH-dependent and micellar solubilization models

Abstract

Biological solubility is one of the important basic parameters in the development process of poorly soluble drugs, but the current measurement methods are mainly based on a large number of experiments, which are time-consuming and cost-intensive. There is still a lack of effective theoretical models to accurately describe and predict the biological solubility of drugs to reduce costs. Therefore, in this study, osaprazole and irbesartan were selected as model drugs, and their solubility in solutions containing surfactants and biorelevant media was measured experimentally. By calculating the parameters of each component using the perturbed-chain statistical associating fluid theory (PC-SAFT) model, combined with pH-dependent and micellar solubilization models, the thermodynamic phase behavior of the two drugs was successfully modeled, and the predicted results were in good agreement with the experimental values. These results demonstrate that the model combination used provides important basic parameters and theoretical guidance for the development and screening of poorly soluble drugs and related formulations.