Protocol to quantify compound retention in Drosophila melanogaster for the pharmacokinetic study of orally administered compounds

Drosophila melanogaster is a valuable tool for intestinal function research. Here, we present a compound retention assay (CORE) to quantify the orally administered compounds that were absorbed, metabolized, or accumulated in the tissues (for example, fat) of D. melanogaster. We describe steps for preparing flies and media, compound administration, and sample collection. We then detail procedures for determining concentrations and calculating CORE values. This protocol circumvents the limitations of bioavailability research in the fruit fly, such as administering precise compound amounts.