The development of new medicine has to pass many steps until it might be used successfully on the treatment of diseases. One important part is the study of its absorption properties, for which standard procedures exist. One kind of experiments is taken and analyzed from the mathematical point of view. Steady state solutions and time profiles are derived, a closer look at measuring errors is possible.
Furthermore a method [1] that allows to reduce coupled systems to a few variables is presented. This method is valid in the limit of a high number of subsystems and nearly coherent behavior. We applied it to a system of coupled Kuramoto oscillators as an example, and to a modified version of the above mentioned absorption system.