Would anyone know if there are any regulatory constraints to use vials of different sizes/weight for a double blind study in Poland, Korea, Taiwan, the Philippines and Japan?

The secondary packaging (box and clinical label) will be blinded so that the site does not need to ensure that an unmasked person receives the IMP. An unmasked pharmacist and monitor will be positioned for the administration and reconciliation activities.

However, there is a concern that the difference of weight might allow one to assume the active/placebo. The difference of weight is approx. 50-100g. We want to ensure that the IMP will be compliant to regulations.

Any insights on this matter would be highly appreciated. Thank you.