Our 99%+ Purity Claim and How It Is Substantiated

Start with the result behind the label

Copy the lot code from the label. On the batch reports page, request the report for that lot and the specification containing the purity criterion. No downloadable lot reports are currently listed there. If the report uses a laboratory sample ID, ask for the record connecting it to the lot.

What an HPLC area percentage measures. The area of a peak is divided by the total area of the peaks included in the calculation. The result depends on what the detector sees and which peaks were integrated. With uncorrected areas, different detector responses can give different areas for the same amounts. The percentage alone cannot tell you milligrams of target peptide per vial. See HPLC analysis and how to read a chromatogram. ^[3]

Keep four questions separate

Read the result against the acceptance criterion in the applicable specification. Also check that the method was intended to measure the attribute you are assessing. ICH Q6A and Q2(R2) explain those principles for pharmaceuticals. A provider’s method and lot record supply the evidence for the material in front of you. ^{[1] [2]}

A threshold is not a certificate

Worked example with fictional identifiers. A container marked DEMO-LOT-B carries the wording “99%+”. A report for DEMO-LOT-A gives a result of 99.2% area. Enter “lot match unresolved” in your review and ask for the document for B. The number on A’s report cannot answer a question about B.

If a report for DEMO-LOT-B also gives 99.2% area, you can record that result on the stated area basis. Before comparing it with the label, check that the criterion uses the same basis. To establish the quantity of target compound in the vial, request the fill basis and a suitable quantitative result. Neither fictional lot represents a Knockout Labs test.

What the claim does not establish

For identification, use the guide to purity and identity. For the proportion of material made up of peptides, read net peptide content. Check salt and counter-ion information when the mass basis is unclear. Sterility, endotoxin and bioburden each require separate microbiological evidence. A purity result provides no basis for a claim about storage stability or suitability for human or veterinary use.

Use the quality hub to find the type of record you need. The testing methods guide and guide to common impurities help with questions about an analytical trace. If a result or limit is missing, the acceptance criteria guide explains how to record that gap.