Guidance for Industry, Q7A Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients
Tracking Label Requirement for Children's Products
Process and test procedures should be flexible to provide for changes as knowledge of the process increases and clinical testing of a drug product progresses from pre-clinical stages through clinical stages.
You would need to know the exact temperature of the storage facility to make an educated guess as to how long before the Def will expire.
Agreed corrective actions should be completed in a timely and effective manner.