In October 2018, the United States Pharmacopeia (USP) hosted a two-day workshop to explore the science of drug

absorption. Experts from around the globe presented some of the challenges associated with drug product development from the perspective of the physiological attributes of the patient (human or canine) and the body site for drug activity. Included in the discussions were methods and approaches for answering complex questions, providing insights into the strengths and challenges of methods available in our biopharmaceutical tool chest. The following is a synopsis of the presentations and the highlights of the discussions that ensued.