Both documents ship with a pharmaceutical raw material, both are printed on company paper, and both are usually filed together. They serve different masters.
The Certificate of Analysis answers: is this lot what we ordered?
A CoA is a batch-specific declaration that defined tests were performed and met defined limits. Its value depends entirely on three details:
- Identity of the lot. Lot or batch number matching the drum, the invoice and the packing list. A CoA without a lot number cannot be matched to goods.
- The specification it was tested against. Pharmacopoeial monograph, or an in-house specification agreed at purchase-order stage. These are not the same thing, and the difference is where disputes live.
- The methods used. A method reference makes the result reproducible. Without one, the number is unauditable.
The CoA is also the document your QC department files to release incoming goods, so an error in it — a missing parameter, a stale template, a signature block without a date — stops the material in the warehouse regardless of whether the powder is fine.
The Safety Data Sheet answers: how do we handle this safely?
An SDS is product-level, not lot-level, and it is about hazard rather than quality. It follows the GHS structure: identification, hazards, composition, first aid, firefighting, handling and storage, exposure controls, transport classification, regulatory information.
Your EHS team uses it for risk assessment, storage segregation, PPE specification and waste disposal. Your logistics provider uses section 14 for transport classification. Note that the SDS carries no assay information and no impurity data — it is not, and never was, evidence of quality.
What to ask for beyond the pair
Depending on the product and the market, a complete file also needs:
- Nitrosamine risk assessment — for any secondary or tertiary amine, or any route using nitrosating conditions.
- TSE/BSE statement — for materials of animal origin, including gelatin capsules and some excipients.
- Allergen and gluten statements — increasingly requested for oral solids.
- Elemental impurity risk assessment — ICH Q3D classification for the route.
- Residual solvent statement — ICH Q3C class assignment.
None of these replace the CoA. They sit alongside it in the CMC section, and they should be requested before the first shipment rather than during an inspection.
Filing that survives an inspection
File the CoA by lot number against the goods-received record, and the SDS by product with a revision date. Retain superseded SDS revisions — an inspection asking "what SDS was in force when this batch was received" is a fair question that a single-file folder cannot answer.
This note describes general industry practice. It is not regulatory advice and does not replace the requirements of your destination authority or your own quality system.