A pre-filled syringe is disclosed, comprising a barrel and a plunger, the barrel having an outlet, the barrel containing a pharmaceutically acceptable solution having a non-physiological pH, wherein the syringe further comprises an ion exchange material. The ion exchange material is provided at a position to allow contact with the pharmaceutically acceptable solution upon ejection of the pharmaceutically acceptable solution from the barrel via the outlet. The ion exchange material is capable of adjusting the pH of the solution from a non-physiological pH, at which the pharmaceutically acceptable solution is stored in order to ensure acceptable shelf life, to a more physiological pH at which the discomfort and/or pain experienced during injection may be alleviated.