How long do process impurities of APIs need to be preserved in the formulation

GMP stipulates that samples of raw and auxiliary materials used in the production of preparations should be kept for at least two years after the release of the product.

The forum inside the gold GMP document PGY-SMP-QC00002 gold document - sample management procedures mentioned that "storage period: other materials should be kept at least until two years after the release of the product using the material, but not more than the expiration date of the material.

If you come across this situation: the raw material is produced in February 13, the expiration date is until January 15. The use of the raw material to produce preparations production release time is February 2014, according to the provisions of the raw material should be retained until February 2016, at this time the raw material has expired,