The bioavailability of insoluble compounds remains one of the biggest challenges to drug delivery. While there are strategies that can be applied at lower dosage levels, it is particularly difficult to formulate for improved bioavailability at high dosage levels. Improving bioavailability can be crucial to creating a dosage form that is easy to use and meets requirements for patient compliance. CoreRx tackles bioavailability challenges for molecules by leveraging our membrane flux in vitro technology. Today, we will discuss how using this technology enabled CoreRx to discern which factors were most important for bioavailability of a model Class IV compound, and led to development of a formulation with ~70% increase in bioavailability.