This chapter aims to explore the use of molecular dynamics (MD) simulations to investigate the solubilization of drugs by various surfactants and excipients. Examples from the literature are presented to demonstrate that MD simulations provide valuable insights into the solubilization mechanisms, and several metrics for predicting drug solubility in complex formulations are also presented and discussed. We also indicate the potential that is to be found in this area by the combination of MD simulations with machine learning methods.