How Accurate Is HPLC Potency Testing?
Short answer
Very accurate, when the method is validated and run properly. HPLC is the standard technique for measuring how much active ingredient a drug product contains. Under ICH Q2(R2), a method is shown to be accurate, precise, specific and linear over its range before results are reported. The biggest real-world factors are the reference standard, sample preparation and whether the sample is representative.
Accuracy vs precision
Two different ideas get lumped together as “accuracy”:
- Accuracy is how close a result is to the true value. Labs demonstrate it by testing samples with known amounts of the compound and checking how much they recover.
- Precision is how close repeated results are to each other: the same analyst on the same day (repeatability), and different days, analysts or instruments (intermediate precision).
A good potency method needs both. ICH Q2(R2), adopted by the FDA as guidance, lists the characteristics a method should be validated for, including accuracy, precision, specificity, linearity and range (FDA / ICH Q2(R2)).
Why HPLC is trusted for potency
HPLC physically separates the active ingredient from excipients, bases and degradation products before measuring it (NCBI StatPearls). Because the measurement is compared with a reference standard of known purity and concentration run in the same sequence, day-to-day instrument drift is accounted for. System suitability checks, such as repeat injections of the standard, confirm the instrument is performing before sample results are accepted.
What can affect a potency result
| Factor | Why it matters |
|---|---|
| Reference standard | The result is only as good as the standard it is compared with |
| Sample preparation | Incomplete extraction from a cream or capsule base reads low |
| Sample representativeness | One capsule may differ from the batch average; labs often test a composite |
| Method specificity | Co-eluting compounds can inflate a peak if the method isn’t specific |
| Storage and shipping | Heat, light or time can degrade the active ingredient before testing |
Reading a potency result
Potency is reported as a percentage of label claim. A product labeled 50 mg/mL that measures 48 mg/mL is 96% of label claim. Acceptance limits come from the product’s specification or applicable standard and vary by product, so a pharmacist or the specification decides pass or fail. Our certificate of analysis states the method, the reference standard and the result for each test.
When to add LC-MS
If a question goes beyond “how much,” such as confirming identity by mass or explaining an unexpected peak, we add LC-MS testing. See HPLC vs LC-MS for when each fits. Learn more about our HPLC testing lab or our compounding pharmacy potency testing.
Related questions
What does percent of label claim mean?
It compares the measured amount of active ingredient with the labeled amount. 9.5 mg measured in a 10 mg capsule is 95% of label claim.
Why might two labs get different potency results?
Differences in reference standards, sample preparation, the specific units tested and storage between tests can all shift results. Validated methods keep those differences small.
Is HPLC better than a home test kit?
Yes, for potency. Home kits can only indicate presence. HPLC measures how much is present against a reference standard.
How long does HPLC potency testing take?
It depends on the product and whether a method exists. We confirm timing with your quote; call 936-379-5515.
Talk to the lab about HPLC potency testing
Tell us what you need tested and we’ll recommend a method and send a quote. Contact us at 936-379-5515 or info@renewlabgroup.com for current pricing, turnaround and sample requirements. Samples can be dropped off at our lab at 6001 Central Crest, Houston, TX 77092.
Sources
Researcher resources
- Shop Bacteriostatic and Sterile Water
- View Our Certificate of Analysis
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Keep reading
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- Can You Use Tap Water in an Ultrasonic Diffuser?
- What Is ICP-MS Testing?
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