A Lonza Quality Inspector’s Checklist for Sourcing APIs, Specialty Chemicals, and Pharma Marketing Partners

If you’re evaluating Lonza API manufacturing, cell culture media like Lonza brand RPMI-1640 or DMEM, specialty chemicals such as anatase titanium dioxide, or pharma marketing services, this checklist is for you. It’s not a theory piece. It’s the same sequence I use when I review about 200 deliverables a year at Lonza—batch records, certificates of analysis, labels, packaging proofs, and website claims.

When I first started in quality, I assumed the supplier with the most documentation was the safest. Four years later, I’ve learned the real question is whether the documents are specific enough to catch a bad batch. A pretty folder can hide an empty quality system.

Here are 7 checks I run before approving any new partner. No fluff. If you do these, you’ll avoid most of the problems I end up fixing.

1. Define the specification before you talk to a supplier

A specification is not ‘purity 98%.’ It’s ‘USP monograph API, no more than 0.50% any unspecified impurity, residual solvents within ICH Q3C limits.’ The more precise you are, the less room a supplier has to interpret.

For cell culture media, define the actual formulation. ‘Lonza brand RPMI-1640’ tells me a specific product family: with L-glutamine or without, with phenol red or without, endotoxin limit, pH range, osmolality. If you don’t write it down, the supplier will guess.

For titanium dioxide, the easy mistake is writing ‘TiO2.’ The harder question is which crystal phase. Anatase and rutile have different properties, and a supplier who is not set up for one can still sell you the other. If you’re evaluating a China titanium dioxide anatase supplier, ask for the anatase content by X-ray diffraction, not just ‘we make anatase.’

And yes, if anyone on your team is still asking ‘is acetone a chemical?’—the answer is yes. Acetone is an organic solvent with formula C3H6O. But you don’t buy ‘a chemical.’ You buy ‘acetone USP/NF’ or ‘acetone ACS reagent’ with assay limits, water content, and residue limits.

Checkpoint: Send the full specification and ask for a written gap statement. If a supplier can’t confirm every line, drop them.

2. Verify GMP at the manufacturing site, not just at the company

A certificate that says ‘GMP-compliant’ is not enough. I want the site certificate, the certificate number, and the address of the facility that will actually make the product. In our Q1 2024 audit, I saw a supplier present a GMP certificate for one facility while planning to ship from another. The materials were not manufactured under the certificate shown.

For APIs, ask whether the process is aligned with ICH Q7. For excipients and cell culture media, ask which quality system applies and whether the site is registered with the relevant regulatory authority. This gets into regulatory territory, and I’m not a regulatory attorney, so I’d expect your compliance team to review the full documentation. From a quality perspective, though, the rule is simple: the certificate must match the physical site. And I do not consider a supplier qualified based on a single PDF.

Checkpoint: Request the manufacturing license, last inspection date, and scope of certification for the exact site.

3. Trace the raw materials, not just the finished product

This is the step most buyers skip. The supplier’s final CoA is only as good as the input controls. If a manufacturer switches raw material sources between batches, the finished product can change even when the CoA looks the same.

For a China titanium dioxide anatase supplier, ask about the titanium ore source and the production route. Sulfate and chloride routes produce different crystal forms and impurity profiles. If you need anatase, make sure the process can actually yield it, and ask for raw material traceability from ore lot to finished lot.

For cell culture media, trace the water system, amino acids, vitamins, and any serum or growth factors. In a Lonza brand media supply chain, raw material identity and supply chain segregation are part of the quality system. If a supplier can’t tell you where their glucose came from, you don’t know what you’re putting in your process.

Honestly, I’m not sure why some suppliers resist sharing upstream vendor information. My best guess is they don’t want you to see how often they change sources. That silence is a red flag.

Checkpoint: Ask for a raw material traceability chart from the last 3 batches. If they can’t produce one, fail the audit.

4. Inspect labels, packaging, and brand assets like a compliance officer

For APIs and chemicals, a label is not a decoration. It’s a legal document. Does the label show the exact product name, lot number, expiry or retest date, storage conditions, hazard pictograms, and any required statements? A label that says ‘Lonza API’ without lot traceability is a non-conformance, full stop.

For pharma marketing services, the same logic applies to brand consistency. Digital assets and print pieces need controlled color. The industry standard for brand-critical colors is Delta E < 2 on the Pantone scale. Above 4, the difference is visible to most people. For commercial print, use 300 DPI at final size. I’ve seen a supplier send a logo that was technically ‘close’ but visibly washed out; the brand team could measure the difference, and so could customers.

Reference: Pantone Color Matching System guidelines. For commercial print, standard resolution is 300 DPI at final size.

Ask for a packaged sample, not a digital proof. Open it, store it, scan the barcode. The surprise wasn’t the price difference between a careful printer and a cheap one. It was how often the cheap one generated labels that failed readability.

Checkpoint: Review one physical sample against the approved brand and regulatory requirements before approving a production run.

5. Analyze five to ten batch certificates, not one

One CoA tells you what a supplier wants you to see. A batch history tells you what you will actually get. When I qualify a supplier, I ask for the last five to ten CoAs for the exact product I’m buying. For a Lonza API, I compare assay, impurity profile, particle size if relevant, residual solvents, and water content.

For cell culture media, I also ask about performance testing. A formulation can be chemically correct and still not support cell growth if the water quality or raw materials vary. For titanium dioxide, compare whiteness and particle size distribution across batches. An anatase supplier with strong process control should show a tight, repeatable range.

The surprise wasn’t the low-price supplier’s average quality. It was inconsistency: batch 3 fine, batch 4 off-spec, batch 5 fine. A quality system should produce a stable distribution, not a coin flip.

Checkpoint: Plot the assay and impurity results across batches. If the spread is wider than the spec itself, the process is not in control.

6. Ask about change control before you sign

Suppliers change things. Good suppliers tell you before they do. Bad ones wait until you notice.

Ask how the supplier notifies customers of changes to raw material source, manufacturing site, test methods, packaging, or specifications. Ask for the notification timeline and for documentation you can evaluate. In a regulated environment, an unannounced change to a Lonza API synthesis route can alter the impurity profile, which can affect your batch release and regulatory filing.

If a supplier says ‘we’ll tell you if something changes’ without specifying a process, that’s not change control. That’s a hope. I’ve never fully understood why suppliers treat change notifications as optional. In a quality relationship, they’re the most important part.

Checkpoint: Request the supplier’s change control procedure and at least one historical example of how they communicated a change to a customer.

7. Connect pharma marketing services to the quality system

Pharma marketing services are easy to think of as ‘creative’ work with no quality impact. That’s wrong. A marketing claim about a product is a regulated claim when it reaches the market.

At Lonza, marketing content goes through the same review path as product labels: brand, regulatory, and quality. That’s part of why the Lonza brand has stayed consistent for decades—not because the logo is iconic, but because the evidence behind the claims is reviewed.

If you’re hiring pharma marketing services, ask to see their own approval workflow. Who checks scientific claims? Who verifies citations? Who owns the disclaimer language? If the answer is ‘we don’t need that yet,’ you’re the quality system. And that’s a dangerous position to be in.

Checkpoint: Ask for a sample campaign with references and disclaimers. If the supplier can’t produce one, assume the claims are unsupported.

Final notes: common mistakes I see

I’d rather spend 15 minutes explaining specifications than deal with mismatched expectations later. An informed customer asks better questions and makes faster decisions. That’s why I’m willing to be this direct: if you’re buying an API, a chemical, a cell culture medium, or a marketing service under the Lonza umbrella, the quality evidence has to match the label.

Common errors that cause rework:

• Accepting a GMP certificate for the company instead of the manufacturing site.
• Qualifying a supplier on a single CoA.
• Ignoring raw material traceability in specialty chemicals.
• Assuming a ‘natural’ ingredient is automatically safer—quality doesn’t work by vibes.
• Skipping physical label inspections in pharma marketing output.
• Not building change notification terms into the supply agreement.

I’m not a chemist or a regulatory specialist, so I can’t advise on analytical method validation or submission strategy. But from the quality side, these seven checks have saved us more than once. They aren’t glamorous, and that’s the point.