Pharmaceutical Analytical Testing: Methods, Rules and Reports
Pharmaceutical analytical testing is the laboratory measurement of what a drug substance or product is, how much of it is present, and what else is in the sample. Labs answer those questions with validated methods, most often chromatography, and report the results against a specification. We are KMD Analytical, an independent third-party peptide testing lab in Chatsworth, California. This guide explains the field in plain terms and shows how the same logic applies when a peptide vial is mailed in for testing.
Summary
- Analytical testing measures identity, strength (assay), purity and impurities, and, where relevant, attributes such as pH and microbial content.
- HPLC is the most widely used technique, and reversed-phase HPLC is the most popular mode. Peptides are a natural fit.
- In US manufacturing, 21 CFR Part 211 requires scientifically sound, documented test methods. Method validation follows ICH guidance.
- A result describes only the submitted sample under the stated method. Read every report with that limit in mind.
- We test mail-in vials by RP-HPLC-UV for $100 to $150 per vial, with 5 to 7 business days typical turnaround. We do not sell peptides.
Table of Contents
- What pharmaceutical analytical testing is
- What analytical testing can measure
- The methods behind the numbers
- How methods are developed and validated
- What US rules expect from a testing laboratory
- Reading a lab report or certificate of analysis
- Beyond HPLC: endotoxin, pH and water
- Turnaround, rush and same day
- What testing costs
- Our perspective
- Send us a vial
- FAQ
- Sources
What pharmaceutical analytical testing is
Analytical testing uses instruments and reference materials to describe the physical and chemical characteristics of a sample. In drug development it starts early. A peer-reviewed primer on drug development explains that preliminary analytical tests characterize the candidate once it is selected and give initial data for the control strategy that later supports commercial manufacturing.
Testing is not the whole quality system. A 2023 LCGC overview notes that Quality by Design builds critical quality attributes into the process, so quality does not rest only on release testing at the end. Testing is the measurement layer inside that system. It tells you whether a given lot or sample matches what was claimed.
Three groups use it most:
- Manufacturers and developers, who need data for batch release, stability and regulatory files.
- Researchers, who need to know the compound in the vial is the compound on the label before they build work on it.
- Buyers and auditors, who check a supplier’s certificate against an independent result.
What analytical testing can measure
The United States Pharmacopeia frames drug quality tests around a short list of attributes. In the USP chapter on product quality tests, the universal tests for oral dosage forms are description, identification, strength (assay) and impurities. Specific tests such as dose content uniformity, pH, minimum fill and microbial content apply to certain forms. A broader academic review lists identity, assay, content uniformity, degradation products, residual solvents, dissolution, moisture, microbial limits and physical attributes among the quality attributes of a drug product.
For a research peptide in a vial, the practical questions narrow to three:
| Question | Attribute | How it is reported |
|---|---|---|
| Is it the right molecule? | Identity | Match or no match against a reference standard |
| How clean is the main peak? | Chromatographic purity | Area % |
| How much peptide is actually there? | Net-peptide content (assay) | mg per vial |
These are different numbers and they do not substitute for each other. Imagine a vial labeled 10 mg. It can show 99% chromatographic purity and still hold far less than 10 mg of peptide, because purity describes the proportions of what was detected and says nothing about the absolute amount. That gap is why content is reported separately.
The methods behind the numbers
HPLC (high-performance liquid chromatography) separates the components of a mixture as they travel through a column, then detects them as they exit. A 2025 review calls HPLC the most commonly used technique in pharmaceutical analysis, used for stability studies, dissolution testing, impurity profiling and standard assays. The same review identifies reversed-phase HPLC as the most popular mode, and notes that specialty modes extend the technique to biological products and peptides.
Other techniques answer different questions:
- Gas chromatography (GC) suits volatile, thermally stable compounds and is frequently used for residual solvents and trace impurities, according to the same review.
- GC-MS identifies compounds from fragmentation patterns compared with spectral libraries, and PMC-indexed work describes it as a direct, fast and reliable method for separating and quantifying drugs and impurities in forced degradation studies.
- LC/MS adds mass data. A Boston University primer explains that mass spectrometers provide molecular weight, structure, identity, quantity and purity information and add specificity.
- HPLC with a diode-array detector (DAD) records spectra across a wavelength range at once. That allows assessment of spectral peak purity and gives a second line of evidence beyond retention time.
How we run it
We use reversed-phase HPLC with UV diode-array detection (RP-HPLC-UV) on an Agilent HPLC-DAD, with quantitation at 214 nm. Identity is a retention-time and UV-spectral match against a reference standard. Every certificate reports identity, chromatographic purity (area %) and net-peptide content (mg per vial).
The content specification is at least 90% of label claim, with no upper cap. A vial that carries more peptide than labeled is reported as measured, not trimmed to a ceiling.
Blends are reported component by component. Each active gets its own row on one certificate, and a blend never gets a single purity number, because one figure would hide which component carries which impurity. You can see how this looks for a real combination on our BPC-157 / KPV / TB-500 blend page.
How methods are developed and validated
A method is only as useful as its demonstrated reliability. ICH Q2(R1) lists the typical validation characteristics: accuracy, precision, specificity, detection limit, quantitation limit, linearity, range and robustness. The guideline recommends at least five concentrations for linearity, an assay range normally of 80 to 120 percent of the test concentration, and at least nine accuracy determinations over three concentration levels.
The framework is being updated. FDA’s 2024 notice states that Q2(R2) provides a general framework for validation and Q14 harmonized guidance on analytical procedure development.
Validation is also proportional to the situation. FDA’s laboratory controls Q&A recognizes that scientifically sound methods that are not fully validated may be suitable in certain investigations of potential quality problems, while results from unvalidated methods carry greater uncertainty. If you need a purpose-built method for a compound, a matrix or a recurring batch check, we offer method development and ongoing testing programs. Details are on our main site.
What US rules expect from a testing laboratory
In US drug manufacturing, laboratory testing sits under 21 CFR Part 211, Subpart I. The eCFR text of Subpart I requires scientifically sound specifications, standards, sampling plans and test procedures, representative and identified samples, and calibrated instruments. It also requires a written stability program under 211.166 that uses reliable, specific methods and results that determine storage conditions and expiration dates.
Three provisions are worth knowing by number:
- 211.165(a) requires laboratory determination of conformance to final specifications, including identity and strength of each active ingredient, before release.
- 211.165(e) requires accuracy, sensitivity, specificity and reproducibility of test methods to be established and documented.
- 211.160(b)(4) requires instrument calibration at suitable intervals under a written program.
The regulation text for 211.160 sets these out. When a result falls outside specification, FDA’s out-of-specification guidance explains that 21 CFR 211.192 requires an investigation to determine whether the cause lies in the measurement or in the manufacturing process.
These rules govern drug manufacturers. We are an independent third-party lab that tests mail-in vials, and a certificate from us reports analytical results on the submitted sample. It is not an endorsement of a product and not a statement about safety.
Reading a lab report or certificate of analysis
FDA’s Q7A guidance for active pharmaceutical ingredients is a useful checklist for what a complete report contains. A report should show the material, lot, laboratory, test dates, methods, acceptance limits, actual numerical results and an authorized approval, and the pieces should agree with each other. Q7A is available on FDA’s guidance page.
A practical review routine:
- Match the sample to the paper. Sample name, lot and receipt date should correspond to what you shipped or received.
- Look for numbers, not just a pass. A result with units and a limit lets you judge it. A bare “pass” does not.
- Check the method. The technique, detection wavelength and reference material should be named.
- Separate the three questions. Identity, purity and content are different results. A certificate that offers only one of them leaves two questions open.
- Read each active in a blend. A blend with one purity figure is not reporting its components.
- Confirm the certificate itself is genuine. Ours is sealed with a SHA-256 hash and carries a unique ID and QR code, and anyone can check it at kmdanalytical.com/verify.
What a result can and cannot say
A result establishes what the stated method found in the submitted, identified sample. HPLC purity is a chromatographic result under that method. By itself it does not establish sterility, endotoxin status, or that every vial in a batch matches the tested one. That is why we report the three results together and why we offer separate tests for other attributes.
Beyond HPLC: endotoxin, pH and water
Some questions need a different test. Bacterial endotoxin testing under USP <85> uses a kinetic chromogenic LAL method, and we report the result in EU/mL. It costs $150 per vial. It is not a sterility test: it measures endotoxin, and it does not tell you whether a sample is sterile. Details are on our endotoxin testing page.
We also measure solution pH ($20) and test bacteriostatic water ($75). Both are listed on our pricing page.
Turnaround, rush and same day
Typical turnaround is 5 to 7 business days, with 7 as the maximum. For urgent work:
- Rush: next business day, a surcharge of +100%. Rush is limited to up to 4 vials, and vials must be received by 12:00 PT.
- Same day: by arrangement only, a surcharge of +150%, with vials received by 10:00 AM PT. It is not available on the order form.
What testing costs
Per-vial pricing falls with volume:
| Vials per order | Price per vial |
|---|---|
| 1 to 4 | $150 |
| 5 to 9 | $125 |
| 10 or more | $100 |
Blends cost +50% per active beyond the first. Group orders are a common way to reach the higher tiers: organizers can pool vials from several members and split the cost. Full details are on the pricing page.
Our perspective
Most of what is written about pharmaceutical analytical testing assumes a manufacturer with its own quality unit. A great many people who need an analytical answer have no such unit. They have a vial and a certificate from the party that supplied it.
We built KMD Analytical for that situation. We do not sell peptides, so we have no stake in any result. We report three things on every certificate: identity against a reference standard, chromatographic purity as area %, and net-peptide content in mg per vial. We keep them separate because each answers a different question, and a certificate that blurs them can look complete without being so.
We also think a certificate should be checkable by someone who was not in the room. That is why each one is sealed with a SHA-256 hash, carries a unique ID and QR code, and can be confirmed at kmdanalytical.com/verify.
kevin
Send us a vial
If you manufacture, develop or sell peptides, or you need to check a supplier’s certificate against an independent result, we test mail-in vials with the method described above. Pick the vial count, add endotoxin or pH if you need them, and mail the samples. Start from our peptide testing service page, or browse the compounds we test and our scope and limitations.
We do not test controlled substances, HGH/somatropin, testosterone or other steroids, or SARMs. Our lab facts page lists methods, prices and our address.
FAQ
What does pharmaceutical analytical testing include?
It covers identification, strength (assay), purity and impurities, plus attributes such as pH, content uniformity and microbial content where they apply. The USP lists identification, assay and impurities as universal tests for oral dosage forms. The specific tests depend on the product and the question.
Is HPLC purity the same as how much peptide is in the vial?
No. Chromatographic purity is the area percentage of the main peak among detected peaks. Net-peptide content is the measured mass of peptide per vial. We report both, plus identity, on every certificate.
Does endotoxin testing show a sample is sterile?
No. Our USP <85> kinetic chromogenic LAL test reports endotoxin in EU/mL and is not a sterility test. It costs $150 per vial.
How long does testing take, and can it be faster?
Typical turnaround is 5 to 7 business days, with 7 as the maximum. Rush gives next business day for a +100% surcharge, limited to up to 4 vials received by 12:00 PT. Same day is by arrangement only.
How do I know a certificate is genuine?
Every certificate is sealed and carries a unique ID and QR code. Enter it at kmdanalytical.com/verify to confirm it.
Sources
- Drug Development 101: A Primer
- Current Good Manufacturing Practice (cGMP): An Overview for the Analytical Chemist
- USP product quality tests chapter
- Understanding Pharmaceutical Quality by Design
- A review on chromatographic and spectroscopic techniques
- Choices of chromatographic methods as stability indicating
- Basics of LC/MS
- ICH Q2(R1) Validation of Analytical Procedures
- Federal Register: Q2(R2) and Q14
- FDA Q&A on CGMP laboratory controls
- eCFR 21 CFR Part 211 Subpart I
- 21 CFR 211.160
- FDA guidance on out-of-specification results
- FDA Q7A guidance
Recommended
- Peptide Testing Service — $150 per Vial
- KMD Analytical Lab Facts: Methods, Prices & Address
- Peptide Testing for Vendors & Brands
- Tirzepatide (LY3298176) Testing
KMD Analytical reports analytical results on submitted samples only. Nothing here is medical advice or a statement that any product is safe or suitable for use.