A medical device for administering a solution, the device including a pump, a reservoir, and a communication structure for connecting the reservoir and the pump, and a line for connecting the medical device to the patient, wherein the medical device is adapted to use a mathematical model in order to determine at any moment a physical or chemical characteristics of the solution, which is contained in the reservoir, wherein the mathematical model takes account of a modification of the solution in the reservoir over the course of time as a function of an exposure to temperature, to humidity, or to pressure of the solution, or ageing or permeability of the reservoir and the medical device is adapted to inform the patient about refilling the solution or changing the reservoir depending on the modification of the characteristics of the solution.
