@westonci
I'm sorry to hear that it's stuck at customs, did you receive a letter from them? You should have received a letter when it's seized.
I have received at least 20 envelopes with all kinds of chemicals with
zero issues, mostly between 100 and 500mg, but even amounts up to 5000mg.
If I am not mistaken I remember your pictures on Reddit of the Setipiprant and PGE2. It's a bit naive by the sender (don't get me wrong: not by you; I''m not here to criticize, but help you). At some point it will definitely get seized! I remember a vial for the PGE2, if that's really into transport, it's naive to think there will be no issues without legal documents. If there are legal documents it can't be seized, but of course it can be lost.
Always send by mail. With PGE2 that's simple with 100mg. When you receive the envelope, immediately remove it's contents and put it in a cryo vial. Those vials I have seen on PGE2 pictures are way too large. You have to press the chemical in the vial, and fill the vial up to the top, then put the cap on it. If the vial is not full, because you have not enough powder your vial is too big. For some chemicals this is not a big deal, but with a 300 USD 100mg chemical I think it's better to be safe than sorry. O, and you don't need an amber glass vial, a plastic cryo vial for laboraty use is perfect, and they are available in all kinds of small sizes.
About 80% of these kinds of chemicals needs to be stored at -20 Celcius. Always check Caymanchem:
https://www.caymanchem.com/pdfs/14010.pdf
I have a cryo vial box with over 40 vials like this in my freezer.
You can call customs if you think it's seized. 100mg of PGE2 isn't something bad, it's not a controlled substance as far as I know, it could be marked as a medicin though; importing unprescribed medicin. Check some Canadian law on this:
http://laws-lois.justice.gc.ca/eng/acts/c-38.8/
Next time you can ask the sender to send it in parts.
Hope this is helpful. Take care