It may vary from country to country. I think the manufacturer should fellow appropriate international and national guidelines and pharmacopeial specifications to manufacture. Whenever manufacturers come across unusual cases like you raised, they should consult experts, and in fact, they should report the case to the regulatory affairs.

If you have robust documentation and methods at your pharmaceutical plant around the storage, sampling and retesting of the API and can show documented evidence that the API still meets required specifications then you can extend the shelf life yourself. The retesting might be more frequent beyond the manufacturer's retest date until you have data on sufficient batches to be confident in extending the retest date.

Manufacturing and labelling of raw materials for use by API manufacturers is outside the scope of ICH Q7. As such, retest and expiry dates, as defined in ICH Q7, do not strictly apply to raw materials and may be used in a different manner by the raw material supplier. Expiry date, as defined in the glossary of [ICH Q7, Section 20], applies specifically to the API. API manufacturers may re-evaluate [ICH Q7, Section 7.5] and then use a raw material after the ‘expiry date’ or ‘retest date’, based on an appropriate scientific and risk-based justification (e.g., understanding of material attributes, testing, and stability). Similar justifications may be used to extend the date by which the material should be re-evaluated. It is the responsibility of the API manufacturer to ensure the raw materials are appropriate for the intended use at the time of use.

You can find avobe information in 'Q7 Implementation Working Group ICH Q7 Guideline: Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients Questions and Answers Section 7.6'.

Also, you can read the ICH guidelines and PIC/S guide to understand the API industrial regulations better.

Thank you everyone for your answers! As a follow up question, is there a guideline explaining how long the retest date can be extended for? Or a simple projection is all it takes? I can't seem to find any solid information regarding that subject.

Thank you once again

No. There was ICH Q6A that stated that raw material specifications must be made statistically and scientifically justified.

But the buyer can propose a new retest date (based on scientifically and statistically supported data) as well right? It's not limited to the manufacturer. I, as a buyer, can do my own stability testing when the retest day is due and propose a new, longer retest date, right??

Yes. If you have the capability. Setting specifications is a 'little bit more' than dipping your finger in the sample and saying it's OK. In addition a regulatory inspector will question why you set a set a new specification (contrary to the manufacturer) rather than using the lot before it expired (FIFO, first in first out).

The regulatory inspector will also be investigating (they will be taking a holistic approach);

1. Have you performed 'forced degradation (FD) as required by Brazil's ANVISA?

2. Have you properly identified and quantitated the related substances (RS)? What are the drivers in an extended specification (management incompetence?).

3. Do you have a CAPA system in place? Do you have a 'Quality Management System (QMS)'?

It may be cheaper to throw out the old lot and order a new lot than answer some embarrising questions!