In vitro lipid digestion models in design of drug delivery systems for enhancing oral bioavailability.

This review focuses on recent progress in the in vitro lipid digestion models and how these models can underpin in vitro-in vivo correlations which are a key element for drug development. A plethora of articles are dealing with development of lipid-based formulations of poorly soluble compounds for oral administration; however, most studies base formulation development and proof of concept on bioavailability studies and do not consider the use of in vitro studies. A major challenge is the development of in vitro models simulating the gastric or intestinal fluids to assess their in vivo performance. The use of in vitro lipolysis models has been proposed as an approach to probe solubilisation in the aqueous phase during the progress of enzymatic degradation of lipid based-formulations. Moreover, the in vitro digestion models, coupled with biophysical methods, offer insights into the mechanisms underlying lipid digestion, by characterising the generated intermediate colloidal phases, and thereby can serve as a screening tool for designing and optimising lipid-based formulations.