In many instances, it is no longer adequate to show that a pharmaceutical or medical device is sterile, but one also must demonstrate that it is “pyrogen free.” This article provides practical information on reducing pyrogens in cleanroom wiping materials prior to production, as well as eliminating residual pyrogens through sterilization.
In practice, pyrogen-free means that it has a level of pyrogens or endotoxins below a pre-defined threshold concentration which is sometimes referred to as “non-pyrogenic.” Pyrogens are fevercausing materials from the cell walls of Gram-negative bacteria. Few methods of sterilization destroy pyrogens. Pyrogen control requires a “defense-in-depth” approach with cleanrooms, clean working surfaces, clean equipment as well as clean chemicals and biologicals. Fabrics and liquids used to clean surfaces in pharmaceutical and biomedical production areas need to be made with minimal bioburden to reduce the level of pyrogens after sterilization. This means starting with clean materials, keeping them clean during processing, sterilizing them effectively and auditing the level of pyrogens in the materials so produced. Such procedures have been found to enable production of cleanroom wiping materials that meet the United States Pharmacopeia 23 pyrogen standard for medical devices that contact the blood or lymph in circulation, <20 endotoxin units/item (EU/item), even though wipers are not required to meet such strict standards at this time.