#1. Whether your supplier has the technical package for your MOH registration.
Ask your supplier if they have documents first, such as Good Manufacturing Practice, Drug Master Files, Drug Manufacturing License, FDA, CEP, etc. Without those docs and proper registration papers, you will have trouble in your customs for your import.
#2. Whether your supplier can arrange safe shipping by air.
To ship chemicals by air, the exporter of chemicals must apply for the certificate of safe air transportation from relevant authorities. It is regarded as a 6.1 type of dangerous goods. You need suppliers who can handle the proper shipping by air for you.
#3. Whether your supplier has a quality guarantee.
Ask your supplier if they can guarantee their quality, whether they have a full refund or goods-exchange policies for any quality issues. You can add those refund or goods-exchange terms into the sales contract before ordering.
#4. Whether your supplier has any reference from their current customers.
A good reference from their current customers will definitely make your supplier more trust-worthy.
If you have positive and satisfactory answers from your chemical suppliers, you can go ahead to order from them.