Described is a seal used in a drug delivery device. In one embodiment, a seal is provided that includes a tongue, a groove and a coating formed on at least one surface of the tongue, the groove or both the tongue and the groove. In another embodiment, a drug delivery device is provided that includes a housing having a top portion and a bottom portion, a tongue formed on the periphery of one of the top portion or bottom portion and a groove formed on the periphery of one of the top portion or bottom portion and configured to receive the tongue, and a coating on the surface of at least one of the groove and the tongue that creates a hermetic seal between the top portion and the bottom portion when the tongue and the groove are in contact.