To identify an alternative swelling medium with a hydrophilic polymer, we have observed that a swelling medium containing only 6 % PEG 2000 and 0.9 % NaCl tailed to protect a hydrophilic coating during electron beam sterilization and sub-sequent storage at ambient and higher temperatures in an accelerated storage stability test. An unacceptably low dry- out time, be-low the specified 5 minutes, was obtained. However, when the biological buffer sodium citrate was added to a swelling medium containing PEG 2000, the performance of the stored catheters was as good as or better than the performance of catheters stored with the conventional swelling medium.
