NJin,
Since you are mentioning, "E&L", I assume that your question is in the framework of ISO 10993-18, Chemical characterization of medical device materials within a risk management process? If yes, justify your E&L testing of your closure system in line with ISO 10993-1, section 6.3.1 (a) "Testing shall be performed on the final medical device, or representative samples from the final device or materials processed in the same manner as the final medical device"
In case your packaged solutions allow direct chemical analysis, you may also consider investigating your device directly for potential extractables and leachables.
HTH,