This case study explores how SeraNovo’s in vitro partitioning assay predicts in vivo exposure for lipid based formulations. Using atazanavir as a representative compound, it highlights how partitioning behaviour, amorphous solubility, and drug loading relate to pharmacokinetic performance. The results demonstrate how SeraNovo’s expertise and purpose designed in vitro setup strengthens IVIVC and provides early directional insight into which formulations are most promising to advance into further development and in vivo studies.