To validate the constructed models, particularly the machine learning models, a 10-fold CV using the training dataset was performed. In addition, an external test was conducted using a test dataset that was prepared using 20% of the entire dataset before model construction. The GUTFW model was also validated using a training dataset and an external test; however, the GUTFW model was based on the mechanism of human intestinal absorption. Thus, no CV was performed, and predictions were made based only on theory.