Expert: Michael Anisfeld - 11/29/2007

Question
QUESTION: Hi Michael,
We are using very large pails (0.75 cubic meters volume)to hold our solid dosage products before packaging. In majority of the cases, packaging does occur within 30 days of the manufacturing. However, there are instances where bulk stays in these pails for 3-4 months. Since these are very large pails, we can't store them at 25/60 conditions to study bulk stability. Is there any other way to establish bulk hold time of 3-6 months, for all of our products? Please advise. Thanks

ANSWER: The critical questions are:
a. how are the bulk pails sealed, and
b. what are the storage temps/humidities.

Try to mimic the pails materials of construction and the seal on a small scale and hold tablets in these "smaller" containers for 6 months to perform a room temperature stability, or at 40oC/75%Rh to simulate an accelerated stability.

---------- FOLLOW-UP ----------

QUESTION: Thanks Michael for your response. How feasible is the scaling down when the wall thickness of the large pail is 7mm. Can a smaller pail with 0.4-0.6mm thickness be proven equivalent to the large pails?

Answer
if the water vapor transmission rate of the wall of the smaller pail equals that of the bigger pail, then no problem.

Certainly not a problem for a metal pail, but for some plastic pails this might be a problem - but I would not reduce the wall thickness of the pail, only the height/width dimensions.