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Magnesium Stearate Specification and CoA: Buyer Checklist (Ph. Eur./USP)
Magnesium stearate specification and CoA checklist: documents, key parameters and Ph. Eur./USP checks for buying vegan, palm oil-free magnesium stearate.
Magnesium stearate is used in very small amounts, usually well below 2% of a tablet blend, yet it has a big influence on how tablets and capsules run on the machine. Small differences between batches can change flow, hardness and disintegration. That is why the magnesium stearate specification and the certificate of analysis (CoA) deserve a careful look before you approve a new supplier or release a batch. This checklist shows which documents and parameters buyers, QA teams and formulators should review.
Why the magnesium stearate specification matters
Magnesium stearate is a lubricant. It forms a thin film on particles and machine parts so that tablets eject cleanly and capsule filling runs smoothly. How well it does this depends on its fatty acid composition, particle size and specific surface area. A grade that is too fine or blended too long can make tablets softer and slow down disintegration. A consistent specification therefore protects your process, not just your paperwork.
Documents to request from your supplier
- Specification: the agreed limits for every parameter, with the pharmacopoeia reference (Ph. Eur., USP, BP).
- Certificate of Analysis (CoA): the measured results of the delivered batch, with batch number, manufacturing date and retest or expiry date.
- Safety Data Sheet (SDS): handling, storage and transport information.
- Origin statements: vegetable origin, palm oil-free status and vegan suitability, if you make these claims for your product.
- Allergen, GMO and BSE/TSE statements: often required for food supplements and pharmaceuticals.
- Elemental impurities statement: for pharmaceutical use, in line with ICH Q3D.
Key parameters on the CoA
| Parameter | Why it matters | Typical requirement |
|---|---|---|
| Identification | Confirms the substance | Complies with the monograph |
| Magnesium content | Purity of the salt | 4.0–5.0% (dried substance) |
| Fatty acid composition | Lubricating behaviour and batch consistency | Stearic acid at least 40%; stearic + palmitic acid at least 90% |
| Loss on drying | Moisture and hydrate form | Not more than 6.0% |
| Specific surface area | Lubrication efficiency, tablet hardness | For example at least 6.0 m²/g |
| Microbiological quality | Product safety | Total aerobic count max. 1,000 cfu/g; yeasts and moulds max. 100 cfu/g; E. coli absent in 1 g; Salmonella absent in 10 g |
| Chlorides and sulphates | Purity | Chlorides max. 0.1%; sulphates max. 1.0% |
| Heavy metals | Purity | Cadmium max. 3 ppm; nickel max. 5 ppm; lead max. 10 ppm |
Always compare the CoA with the current edition of the pharmacopoeia you work to and with your own specification.
Ph. Eur., USP and BP
Most magnesium stearate for tablets is supplied as a multi-compendial grade that meets Ph. Eur., USP and BP at the same time. The monographs are very similar but not identical, for example in the way the fatty acid composition is reported. If your registration refers to one pharmacopoeia, check that the CoA states compliance with exactly that one. For food supplements, the grade should also meet the EU purity criteria for food additive E470b.
Vegetable origin and palm oil-free grades
The fatty acids in magnesium stearate can come from animal fats, palm oil or other vegetable oils. Many brands of food supplements and clean-label products now ask for vegan and palm oil-free magnesium stearate. If you make such a claim, ask for a written origin statement for each grade and keep it with your batch documents.
Checklist for incoming goods
- Batch number on the bags matches the CoA
- All CoA results are within your specification
- Retest or expiry date leaves enough time for your production plan
- Bags are closed, dry and undamaged
- Origin and allergen statements are on file for this grade
- A sample is retained for later comparison
FAQ
What is the CAS number of magnesium stearate?
The CAS number of magnesium stearate is 557-04-0, and the EINECS number is 209-150-3.
How much magnesium stearate is used in tablets?
Usually 0.25–1.0% of the final blend. The right level depends on your formulation and should be confirmed in trials.
How should magnesium stearate be stored?
Store it in closed bags in a cool, dry place. Use the first-in, first-out principle and check the retest date before use.
Magnesium stearate from biolla chemicals
biolla chemicals supplies vegan, palm oil-free magnesium stearate (E470b, CAS 557-04-0) in USP / BP / EP quality to pharmaceutical, food supplement and food manufacturers across Europe. It is available from stock in Germany in 15 kg sacks. Every batch comes with a CoA to Ph. Eur., and the shelf life is three years from the date of manufacture. Specification, CoA, SDS and samples are available on request.
See all details on our product page: Magnesium Stearate, vegan & palm oil-free, USP/BP/EP
Related articles:
- Vegan magnesium stearate (E470b): plant-based and palm oil-free
- Magnesium stearate in vitamin tablets
- Microcrystalline cellulose specification and CoA: MCC buyer checklist
Request a quote, specification or sample:
- Contact form
- Email: info@biolla.de
- Phone: +49 40 67 555 155
