A method of producing a ready-to-use medical device with a functional coating includes the steps of bringing the medical device, at least with its functional coating, in contact with a composition which prevents or retards degradation of the functional coating and sterilizing the medical device and the composition via radiation. A method leads to an improved product, namely an improved ready-to-use medical device which does not suffer a loss of quality during sterilization and storage. The composition comprises carboxymethyl cellulose or a derivative or salt thereof and/or an antioxidant selected from gallic acid or a derivative thereof.