While this question has a pretty standard philosophical response (many regulators would like to see it at 30 days or less), practical requirements such as packaging, labelling, contract testing, sterilization, etc. can stretch the availability of product for start of stability well beyond the ideal timeframe, especially if these various stages require international shipping in addition to fitting into tight schedules on a contractor’s calendar. A slight delay in any preceding step can result in missing a scheduled window and force the product to “get back in line” for the contractor’s next available opportunity.
To address the impact of these hurdles, some companies will insert extra test or interim release points to demonstrate the continued integrity of the product as well as what expenditures of the stability shelf life budget occur as a result of the extended process. The most common of these is having an SOP that invokes a Time Zero Test point if the minimal allowed interval between release and start of stability (say 30 days) is exceeded. This generally allows the Stabilitarian to see the impact of the subsequent study without the influence of the earlier processing steps.
Over the years, there have been quite a few approaches voiced by Stabilitarians on this topic. This would be a good opportunity to have those inputs updated in this particular discussion.
