Because leaching of extractable substances into pressurized formulations should be minimized,valve materials and other components that are in contact with the product meet the requirements under Elastomeric Closures for Injections á381ñ(Note that under Physicochemical Test Proceduresin á381ñthe directions for preparing a sample require pre-extraction,which may cause an underestimate of the amount of extractables from a given component.)See also Aerosolsunder Pharmaceutical Dosage Forms á1151ñ.