What a certificate of analysis for an API or excipient must contain
A certificate of analysis is short, but every line on it has a job. Here is what a complete certificate for an API or an excipient contains, and why each item is there.
What must a certificate of analysis for an API or excipient contain?
It must identify the material, grade and pharmacopoeial edition; the batch number with its manufacture and retest or expiry dates; the manufacturer and the site that made and tested it; every test in the agreed specification with its acceptance criterion and actual result; and a dated release by a named person in the quality unit.
Most buyers learn what a certificate of analysis should contain the hard way: a shipment is held at the warehouse because the certificate is missing a test, a site name or a signature that the receiving quality unit expects. The document itself is short, but every line on it carries a job. When one of those lines is absent, the certificate stops being able to do what it is for, which is to link one batch of material to the tests that released it.
This article sets out the contents a buyer should expect on a certificate for an active pharmaceutical ingredient or an excipient, and why each item is there. It describes the shape of a complete certificate. The exact tests and acceptance criteria come from the specification you agreed and the rules of your own market, not from any general list.
What are the certificate of analysis requirements for an API or excipient?
A complete certificate answers four questions without the reader needing another document: what the material is, which batch it describes, who made and tested it, and what the tests found against which criteria. Everything a buyer checks later depends on those four answers being on the page.
Identification of the material
The certificate should give the product name as it appears in the specification, the grade, and the pharmacopoeia the material is tested against where one applies, with its edition. A certificate that says only the common name of the substance, with no grade and no monograph reference, cannot be matched to a specification with confidence. For an excipient, the grade matters as much as the name, because the same substance is often sold in grades meant for food, technical use and pharmaceutical use.
Identification of the batch
The batch or lot number is the anchor of the whole document. Beside it, a buyer should expect the date of manufacture and either a retest date or an expiry date, depending on how the material is controlled. Many certificates also show the batch size. Where the material has been repacked or relabelled by someone other than the manufacturer, the original batch number should still be traceable, either on the same certificate or on a linked one.
Identification of the manufacturer and the testing site
The certificate should name the manufacturer and the address of the site where the batch was made. If testing was done at a different site or at a contract laboratory, that should be clear too. This is the line that connects the certificate to the site's GMP status and to any file the buyer relies on, so a certificate that names only a distributor or a sales office leaves a gap that nothing else on the page can fill.
What should the results section show?
The body of the certificate is a table. Each row should give the name of the test, the acceptance criterion and the result. Where the specification refers to a method, such as a pharmacopoeial method or an in house method, the certificate should say which one. A buyer reading it should be able to place each row beside the matching row in their own specification and compare them directly.
The tests normally cover appearance, identification, assay, and the impurities and other attributes that the specification controls. For many APIs that includes related substances, residual solvents, water content and any physical properties that matter for the dosage form. For many excipients it includes functional properties that affect how the material behaves in manufacture. Which tests are required, and at what acceptance criteria, depends on the monograph, the registration and the market.
Numbers where the test gives numbers
Where a test produces a value, the certificate should report the value, with the unit. A result written as complies is acceptable for tests that are pass or fail by nature, such as appearance or identification. For assay, water content or a named impurity, a value lets the buyer see how close the batch sits to its acceptance criterion and compare it with earlier batches. A certificate that reports complies for every quantitative test is incomplete, even if each statement is true.
A complete certificate stands on its own. It names the material and grade, the batch and its dates, the manufacturer and testing site, every test in the agreed specification with its criterion and result, and the person who released it. If any of these is missing, the certificate cannot link the batch to the tests that released it.
Who should sign a certificate of analysis?
The certificate should show that the batch was released by the manufacturer's quality unit. In practice that means the name or position of the person responsible, a signature or an approved electronic equivalent, and the date of release or issue. A certificate with no signatory, or with a signature that cannot be connected to anyone in the quality function, records results without recording that anyone stood behind them.
A clear statement of conformity is also expected, usually a line saying that the batch meets the stated specification. That statement means more when the specification it refers to is identified by name or number, so that it cannot later be read as referring to a different version.
Does an excipient certificate differ from an API certificate?
The structure is the same, but the emphasis shifts. Excipients are often produced in large volumes for several industries at once, and the pharmaceutical grade may come from the same plant as other grades. That makes the grade statement, the manufacturing site and the traceability of the batch especially important. Excipient certificates also tend to carry functional tests, such as particle size or viscosity, that are critical to how the material performs in a formulation even when the monograph treats them as optional.
Excipient makers that follow the industry guidance on excipient GMP and on certificates of analysis usually present this information in a consistent way. A certificate that departs from that pattern is not wrong for that reason, but it deserves a closer read.
What does a certificate not need to contain?
A certificate is a summary, not a full record. It does not normally include chromatograms, raw data or method validation. Those sit in the manufacturer's batch records and may be requested under a quality agreement or reviewed during an audit. Nor does a certificate need to repeat the full specification document, provided each test row carries its acceptance criterion. Asking for supporting data is reasonable when a result looks unusual. Expecting it on every certificate is not.
Once you know what a complete certificate looks like, the next step is to check a certificate of analysis before you buy. The dates on it are explained in our guide to retest dates and expiry dates, and the impurity rows in reading an API impurity profile. For excipients, see excipient GMP and the IPEC guidance.
NJMC Medical Supplies Co., Ltd is a trading and consultancy company in Nanjing, China, supplying medical equipment, medical consumables and active pharmaceutical ingredients to healthcare institutions, sourced from manufacturers in China and India.
Frequently asked questions
Is a certificate of analysis from a distributor acceptable?
A distributor may issue its own covering certificate, but the manufacturer's original certificate should travel with it unchanged. Only the original names the site that made and tested the batch and the quality unit that released it. A distributor's certificate on its own tells you who sold the material, not who produced it or tested it.
Should every result on a certificate be a number?
No. Tests that are pass or fail by nature, such as appearance and identification, can be reported as complies. Tests that produce a value, such as assay, water content or a named impurity, should report the value with its unit, so that the buyer can see how close the batch sits to its acceptance criterion.
Does a certificate of analysis need to include raw data?
Not normally. A certificate summarises the results; chromatograms, raw data and method validation stay in the manufacturer's batch records. A buyer can ask for supporting data when a result looks unusual, or review it during an audit, and a quality agreement can set out when the manufacturer must provide it.
What should an excipient certificate add that an API certificate may not?
An excipient certificate should state the pharmaceutical grade clearly, because the same substance is often made in food and technical grades too. It should also report the functional properties that matter for your formulation, such as particle size or viscosity, where your specification controls them.
Check a certificate of analysis. PharmaTrust by NJMC, our own software, reads a certificate against the applicable specification and lists the points to raise with the supplier. Certificate check
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