Nanoparticles are often used to increase the dose of a substance that can be delivered to a system. A dose considerably higher than for a saturated solution can be achieved. The exchange rate of molecules from the particles and a solution is an important factor for the usefulness of the particles. Therefore, modelling of dissolution or growth of particles is of big interest. Another issue for investigation is how quickly new nanoparticles nucleate, i.e. how quickly tiny particles are created in a supersaturated solution. Ostwald ripening, which is the mechanism by which bigger particles in a solution growth of the expense of smaller partcles, is yet another topic for modelling.