The present invention relates to medical devices, in particular autoinjectors and syringes having one or more thermochromic response indicators that are sensitive to temperature changes of a drug formulation or solution. The present invention provides for a pre-filled delivery device comprising a syringe, a cartridge, or a capsule having a barrel, where the barrel is marked on the outer surface with a first thermochromic indicator, and wherein the thermochromic indicator is responsive to temperature changes of the drug formulation or solution within the barrel.
