A pre-filled syringe assembly having a tamper evident tip cap is provided for indicating if the contents of the syringe assembly have been compromised. The syringe barrel has an interior chamber which defines a pressure therein and is sealed at the proximal and distal ends by a first and second seal, respectively, to maintain this pressure. The second seal is formed of a deformable material and a tip cap is located about the second seal and distal end of the syringe barrel. This tip cap includes a viewable indicator representing a change in state of the syringe contents. The indicator has a portion positioned in contact with the second seal such that the first distinguishing feature is viewable through a portion of the cap. Tampering of the contents within the interior chamber causes a change in pressure and movement of the indicator indicating tampering of the syringe assembly.
