Summary Millions of animal experiments are still used in drug development each year. We want to save animal experiments in this field. By employing the fiber optic concentration monitor, we can study the dissolution process of drugs in detail. This process is crucial for bioavailability and effectiveness of drugs. We shall study the physico-chemical processes that take place at the surface of drug particles. We will also develop fully artificial models that mimic the conditions in vivo that will enable us to explore many drugs and dosage forms (e.g. amorphous solid dispersions, oral films), for time resolved absorbable fractions. This will pave the path from empiric drug development with many animal tests towards informed computational modelling to find the best drug formulations.