Independent analysis puts a CPC dulaglutide lot at 95.9%, against 94.7% on the certificate
The supplier has not disputed the finding. It has not explained the gap either.
TheCompound Journal
Reporting on incretins, compounding & the peptide supply chain
Certificates
What the Journal asks when a document arrives unsigned, and what the answers have been.
The last block on a properly built certificate is the part the trade ignores entirely, and it is the part that determines what the document is worth in an argument. Somebody performed the tests. Somebody reviewed the results. Somebody authorised the release of the batch on the strength of them. In a regulated plant those are distinct roles with distinct signatures and the separation is a control rather than a courtesy: the person who ran the assay does not get to decide unaided that the batch passes.
The bottom of a certificate carries the dates, the signatures and any boilerplate. A complete footer gives the date of manufacture, the date of analysis, and either a retest date or an expiry date with the convention named. It gives the name and role of the person who performed or compiled the testing, and separately of the person who reviewed and approved it. It states the storage conditions under which the stated properties hold. And it states, in a research-chemical context, the research-use-only restriction.
The two-signature convention is worth explaining because its absence is so universal here that its purpose is forgotten. Separating performance from approval is a control against a single person’s error or judgement determining a release. It is cheap, it requires no equipment, and it is the ordinary practice in every regulated laboratory. Its function is not ceremonial: it means that when a document turns out to be wrong, there is a record of who reviewed it and on what basis.
What the footer should not carry is a signature rendered as a reused image with no accompanying name. That is not evidence of anything improper on its own — scanned signature blocks are common in legitimate commerce — but it removes the one piece of information the block exists to supply, which is the identity of a person who can be asked.
An unsigned certificate is a statement with no author. It may be entirely accurate; it is simply not attributable, and attribution is most of what a release document does. The regulated convention of two signatures — one for the analyst who performed or compiled the work, one for the reviewer who approved its release — exists because release is a decision and decisions benefit from a second reader.
What the Journal looks for is narrower than a wet-ink signature, which nobody expects in a scanned document. We look for a name and a role. “Analysed by: L. Wen, Analytical Chemist. Approved by: Q. Zhang, QC Manager” is worth more than any flourish, because it identifies people who can be asked a question. A certificate signed with an illegible mark and no printed name has supplied the ceremony and withheld the content.
Of the twenty companies in the dossier programme, eleven print a name in the signature block, four print a role without a name, and five print neither. Two of the eleven print two names in the regulated pattern. These are documentary counts and nothing more; a company with no name on the certificate may have impeccable internal records, and several of them, when asked, produced signed internal release records promptly. The point is that a buyer cannot see any of that from the page.
No two real chromatographic runs produce identical baselines. Two documents carrying the same trace carry the same injection.
On reading certificates as documentsAn accreditation logo on a letterhead means a body has assessed a laboratory against the international standard for testing competence and granted accreditation for a defined scope of methods. The scope is the part that matters and it is published: accreditation bodies maintain public registers listing, for each accredited laboratory, the tests and techniques covered. A laboratory can be validly accredited and the specific test on your certificate can lie outside its schedule.
Checking this takes a few minutes. Find the accreditation number on the document, look it up on the relevant national body’s register, and read the scope. What you are looking for is whether the technique used for your test — reversed-phase HPLC purity, mass spectrometric identity, water determination — appears. Where it does, the accreditation is doing work. Where it does not, the logo is a true statement about the laboratory and says nothing about the test in front of you.
The standard itself is clear that reports must identify what was and was not covered, and that accredited status attaches to activities rather than to organisations as a whole.1 The Journal makes this check on any certificate it intends to cite, and reports the result. It is the single most under-performed piece of due diligence in this market, principally because almost nobody knows the registers exist.
| Test | Method | Specification | Result |
|---|---|---|---|
| Appearance | Visual | White to off-white lyophilised powder | Conforms |
| Identity | ESI-MS, Q-TOF | 4111.1 Da (monoisotopic), ±10 ppm | 4111.14 Da (+7 ppm) |
| Purity | RP-HPLC, 25–45% MeCN over 40 min, 214 nm, threshold 0.05% | ≥98.0% (area) | 98.7% |
| Single largest impurity | As above | ≤1.0% | 0.42% |
| Peptide content | Elemental N determination | ≥85% | 91.3% |
| Water | Karl Fischer | ≤8.0% | 4.1% |
| Acetate content | Ion chromatography | Report result | 6.8% |
| Residual solvent (MeCN) | Headspace GC | ≤410 ppm | <50 ppm |
| Solubility | Visual, 1 mg/mL in water | Clear, colourless | Conforms |
| A composite constructed by the Journal from the best certificates in our dossier programme; no single supplier in the programme issues a document containing every one of these rows. Reproduced as a reference against which real certificates can be compared, not as a specification anybody is obliged to meet. | |||
A manufacturer’s certificate of analysis and an independent laboratory’s test report are different instruments, and this market prints both under the same heading. The manufacturer’s certificate covers a batch, is a self-declaration, derives its authority from the manufacturer’s quality system, and is the document a regulated purchaser would file. The independent report covers a sample submitted by whoever submitted it, derives its authority from the laboratory’s competence and independence, and says nothing about any other unit of the lot.
Each has a virtue the other lacks. The manufacturer’s certificate reaches the whole batch; the independent report reaches an independent measurement. Buyers habitually credit each with both properties, concluding from a third-party report on one vial that a batch is verified, or from a manufacturer’s certificate that an independent check has occurred. Neither inference holds.
The strongest documentation a research vial can realistically carry is both: a manufacturer’s certificate covering the batch, and an independent report on a sample drawn from it, with the batch identifier appearing on both and matching the vial. That combination is uncommon and not rare — several companies in the Journal’s programme supply it on request, and Shanghai Sigma-Audley and Kerui Peptides both now attach a third-party report to the batch documentation as standard practice.
Four rules, arrived at over two years and revised twice. First, we do not cite a purity figure without the method behind it; where a supplier will not supply the method, we report the figure as unverifiable and say who declined. Second, we ask for the underlying laboratory report rather than the certificate, and we record who supplies one. Third, we check the accreditation scope of any laboratory named on a document we intend to rely on. Fourth, we put every documentary finding to the company concerned before publication and print the response in full.
The fourth rule is the one that has changed our coverage most. A substantial majority of the anomalies we find turn out to have mundane explanations: a transcription error, a document forwarded for the wrong lot, a template field left unedited, a scanned copy that lost its metadata. Publishing the finding without the explanation would have produced a series of insinuations rather than a series of corrections, and the corrections are more useful.
The rules also mean we publish less than we could. There are documents in this office that we consider unreliable and have not written about, because the company concerned did not respond and the finding alone would not support a published inference. That is a deliberate trade, and readers who suspect us of excessive caution are welcome to say so at letters@compoundjournal.com, where several already have.
Readers who take one habit from this piece should take the first minute of the ten-minute check. Find the batch number on the vial. Everything else on the document is a claim about a defined quantity of material, and if the vial is not identifiably part of that quantity then the rest of the page is a well-drafted statement about something else.
Selected from correspondence received on this article. Writers are identified by initial, surname and city, verified before printing. Replies are from the desk that filed the piece or from the standards editor. Write to letters@compoundjournal.com.
I supply research peptides and I want to push back on the specification column point. We sell from a catalogue of six hundred products. Writing a meaningful individual specification for each would take a year of somebody’s time, and a generic one would be exactly the decorative limit your article criticises. What would you actually have us do?
— R. Hollenbeck, Spokane, WA
A fair challenge. Our answer is that a generic limit stated honestly is better than no limit at all, provided the typical result is also published so a reader can see the margin. What we object to is a decorative limit presented as a control. Publishing your process capability alongside it removes the objection entirely, and costs you a spreadsheet.
The supplier has not disputed the finding. It has not explained the gap either.
The Journal submitted the sample and paid for the analysis. The vendor was told in advance.
What a laboratory can and cannot know about the provenance, storage history and representativeness of what lands on its bench.
Reported from the analysis, not from a warning notice.
An isoaspartate rearrangement changes the molecule and not the mass. A method that confirms identity by molecular weight alone will report it as the parent compound.
Calibration drift is real, unremarkable, and the reason serious laboratories run internal standards.