| abstract |
A drug delivery device is provided, comprising a reservoir adapted to contain a liquid drug, an outlet, and expelling means for, in a situation of use, expelling a drug from the reservoir via the outlet. The device further comprises a light source (575) adapted for directing a beam of light through the drug, and detection means (576, 577) allowing a transmission characteristic of the light beam through the drug to be detected. The detecting means may be either in form of a transparent area allowing a user to inspect a portion of the device through which the light beam is directed, or light detection means used in combination with an electronic controller. |