One of the primary batches of the drug product should be tested for
antimicrobial preservative effectiveness (in addition to preservative content) at
the end of the proposed shelf life. The drug product specification should
include a test for preservative content, and this attribute should be tested in all
stability studies.
Extraction/leachable studies are generally one-time studies; however, if
multiple types of containers/closures are employed for packaging, then
additional studies could be recommended.
