Predicting phototoxicity involves a combination of in vitro testing and computer-based models. The 3T3 Neutral Red Uptake (NRU) phototoxicity test is a widely used in vitro method that assesses the potential of a substance to cause phototoxic effects. Computational models, such as Quantitative Structure-Activity Relationship (QSAR) models, predict phototoxicity based on the chemical structure of compounds.