Abstract: A respiratory interface device (10, 20, 30, 40, 50, 60, 70, 80) comprising a main body (12, 22, 32, 42, 52, 62, 72, 82) that includes a fluid conduit adapted to be connected to a breathing circuit, and a sealing member (15, 25, 35, 45, 55, 65, 75, 85) adapted to engage a surface of a patient, such that the fluid conduit is in fluid communication, in use, with an airway of the patient, wherein the sealing member (15, 25, 35, 45, 55, 65, 75, 85) includes a plasticising agent, and a barrier member (18, 28, 38, 48, 58, 68, 78, 88) is provided between the sealing member (15, 25, 35, 45, 55, 65, 75, 85) and the main body (12, 22, 32, 42, 52, 62, 72, 82) of the device(10, 20, 30, 40, 50, 60, 70, 80), the barrier member (18, 28, 38, 48, 58, 68, 78, 88) at least impeding the migration of plasticising agent from the sealing member (15, 25, 35, 45, 55, 65, 75, 85) to the main body (12, 22, 32, 42, 52, 62, 72, 82) of the device(10, 20, 30, 40, 50, 60, 70, 80).