With continually growing fields of applications for ENM and immense technological and economic potential, it needs to be kept in mind that nanotechnology also entails potential risks due to their high surface to volume ratio, some nanomaterials are chemically more reactive. What happens to the nanomaterials after being taken up by humans? How can one explain, and properly predict for example the unexpectedly fast clearance of BaSO4 from the lung, despite its insolubility in water? To determine the fate and the hazard potential of a nanomaterial within the human organism or the environment, it is mandatory to understand how an ENM interacts with physiological media. Essential for the understanding of the behavior is the determination of dissolution, transformation and dosimetry of ENM in relevant media. This work addressed the extrinsic properties of ENM for grouping and read across by assessing the dissolution and transformation in an abiotic flow-through dissolution setup, as well as investigation the limitations of current in vitro dosimetry setups.