Evaluation of fasted and fed simulated intestinal fluid in predicting poorly soluble drugs using 9-point approach

The extent of absorption of orally administered drugs depends on their solubility in human intestinal fluid (HIF). Simulated intestinal fluid is used as biorelevant media to determine drug solubility in vitro. In this study, 9-point bioequivalent simulated intestinal media was used to assess the solubility of three poorly soluble drugs (prednisolone, valsartan, and itraconazole) in the fasted and fed state using the shake flask method. The composition of simulated intestinal fluid was found to influence the equilibrium solubility results. This influence varies depending on the compound's ionisation nature (neutral, acid, base).