Cleaning Validation Controls That Prevent Softgel Recalls

In my experience, contamination recalls don't happen because someone made a careless mistake. They happen because a quality system allowed a gap to persist — sometimes for months — before a finished product reflected it. The Haleon voluntary recall of Gas-X Extra Strength Softgels 125mg in June 2026, involving potential contamination with a diluted propylene glycol-based substance across four distributed lots, is a useful case study in exactly this kind of gap.

Propylene glycol is an interesting contaminant to find in a finished softgel. FDA classifies it as generally recognized as safe (GRAS), so the health risk is relatively limited. But its undeclared presence in a diluted form — one that suggests it arrived via process contact rather than formulation intent — points toward a specific failure zone: equipment cleaning, equipment lubrication, or both. The FDA enforcement record for this recall (published June 4, 2026) confirms that four lots distributed on or about April 13, 2026 to the consumer level were affected. The product was pulled before that question could be answered in the field.

That's the lesson here. Not "Haleon had a problem" — every OTC manufacturer is one control gap away from a similar event. The more productive question is: what would have had to be in place to catch this before those lots shipped?

Where Propylene Glycol-Based Contamination Comes From

Softgel encapsulation is a precision manufacturing process. Gelatin shells form from a molten ribbon, fill material is metered and injected, and rotating die rolls seal the capsules at production rates that can reach hundreds of thousands of units per hour. That equipment requires lubrication, and many pharmaceutical-grade lubricants carry propylene glycol as a base or carrier. Cleaning agents in pharmaceutical manufacturing also frequently use propylene glycol-based formulations — they're effective, low-toxicity, and compatible with most equipment surfaces.

That makes them a logical choice, but it also means they're present in the manufacturing environment in diluted forms during changeover, sanitation, and maintenance cycles.

The contamination path, in most cases like this, runs one of three routes:

1. Cleaning agent residue — a cleaning solution wasn't fully rinsed, or the rinse validation didn't adequately represent actual equipment configuration.
2. Lubricant intrusion — a seal, bearing, or lubrication point allowed contact between lubricant and product-contact surfaces.
3. Equipment maintenance residue — a maintenance activity introduced a substance that wasn't tracked through the batch record.

Any one of these can slip through if the quality system isn't specifically designed to catch it. And in a high-speed, high-volume OTC manufacturing environment, pressure to maintain throughput creates conditions where these gaps widen over time, quietly, until a lot ships with something in it that shouldn't be there.

What 21 CFR Part 211 Actually Requires

The regulatory framework for preventing exactly this type of contamination is unambiguous. 21 CFR 211.67 requires that equipment and utensils be cleaned, maintained, and sanitized at appropriate intervals to prevent malfunctions or contamination that would alter the safety, identity, strength, quality, or purity of the drug product. The regulation isn't advisory — it's a hard requirement that cleaning procedures be written, followed, and documented.

More specifically, 21 CFR 211.67(b) requires written procedures for cleaning and maintenance that include, at minimum: assignment of responsibility for cleaning, maintenance schedule, description of cleaning methods and cleaning agents used, and documentation of cleaning performance. This isn't a suggestion to document; it's a requirement that the documentation exist and accurately reflect what was done.

21 CFR 211.68 extends this to automatic, mechanical, and electronic equipment, requiring that such equipment be calibrated, inspected, or checked routinely to ensure proper performance. For softgel encapsulation lines — which are highly automated — this means the maintenance and inspection program needs to specifically address lubrication points at or near product-contact surfaces.

21 CFR 211.192 requires that all production and control records for each batch be reviewed and approved by the quality control unit before release for distribution. A batch record review that is genuinely rigorous — not just a box-check exercise — would flag anomalies in cleaning logs, equipment maintenance records, and any out-of-specification observations that arose during production.

Equipment cleaning deficiencies under 21 CFR 211.67 are consistently among the top 10 most-cited cGMP violations in FDA drug manufacturing inspections. The gap between what the regulations require and what actually happens in practice is where most contamination events live.

Cleaning Validation: The Control Most Often Underbuilt

Cleaning validation is the cornerstone of contamination prevention in pharmaceutical manufacturing, and it's also the area where I find the most gaps in client audits. FDA's Guide to Inspections of Cleaning Validation, though published in 1993, remains the agency's primary reference on what's expected, and its standards have been reinforced through subsequent inspection practice and warning letter citations over the past three decades.

A robust cleaning validation program establishes, for each piece of equipment:

• Worst-case products — which product or cleaning agent residue is hardest to remove from each surface
• Worst-case conditions — the equipment configuration, surface area, and contact time that presents the greatest cleaning challenge
• Recovery studies — analytical data demonstrating that the swabbing or rinse-sampling method can actually recover residues from the equipment surface, not just detect them in solution
• Acceptance criteria — specific limits for residual contamination, typically expressed as a fraction of the minimum therapeutic dose or as a maximum surface residue in micrograms per square centimeter

FDA's Guide to Inspections of Cleaning Validation holds that residual contamination should be at or below 10 ppm in the next product, or at or below 0.001 of the normal therapeutic dose of the previous product, or below the limit of analytical detection — whichever is most stringent. For propylene glycol specifically, if the cleaning agent or lubricant carrying it isn't even listed among the substances being validated, this calculation never gets made.

Cleaning validation tends to break down in three predictable places. First, the validation is performed under ideal conditions but production runs under realistic, messier ones. Second, the validation doesn't cover every equipment configuration actually used in production — dies are swapped, extension pieces are added, and the validated configuration drifts from reality. Third, and most commonly, cleaning validation is treated as a one-time event rather than a living program that gets revalidated when equipment or cleaning agents change.

Equipment Maintenance Controls

Cleaning validation is only half the picture. The other half is what happens between production runs, during maintenance windows, and when equipment is serviced.

A meaningful equipment maintenance program for contamination prevention includes:

• Lubricant inventory control — only approved, pharmaceutical-grade lubricants permitted on product-contact or near-contact surfaces, with use documented in equipment logs
• Lubrication point mapping — a physical map of each piece of equipment identifying every lubrication point, its proximity to product-contact surfaces, and the acceptable lubricant type for each
• Maintenance documentation integrated into batch records — any maintenance activity performed on equipment within a defined window before or during production captured in the batch record, not just in a separate maintenance log
• Post-maintenance verification — after any maintenance that could have introduced a contaminating substance, a verification step (visual inspection, swab test, or dedicated rinse) required before production resumes

The key principle is traceability. If a batch record shows that equipment maintenance was performed, and the batch later contains an unexpected contaminant, the quality system should make it possible to trace the contamination path. If that traceability doesn't exist, the investigation starts from nearly nothing.

Comparing Strong and Weak Contamination Prevention Systems

The difference between a quality system that catches this kind of issue before product ships and one that catches it after is mostly a function of layered controls. Here's how those systems compare:

A manufacturer with the right side of this table built out is unlikely to ship contaminated product. A manufacturer on the left side can go years without a visible problem — right up until a lot gets pulled.

Detection Systems: The Last Gate Before Distribution

Even with robust cleaning validation and equipment controls, finished product testing is the final gate before a lot ships. For OTC softgels, this typically includes dissolution testing, appearance and visual inspection, and identity and assay testing for the active ingredient. What it often doesn't include is any analytical test that would detect unexpected manufacturing residues.

A control strategy built around known contamination risks would include release testing methods specific to those risks, per ICH Q10 Pharmaceutical Quality System guidance. If a manufacturer's finished product specifications include no analytical method for propylene glycol or propylene glycol-based substances, a contaminated lot can pass every release test and ship to retailers.

The U.S. OTC drug market generates approximately $55 billion in annual retail sales. Drug recalls attributable to contamination and foreign substance issues represent hundreds of enforcement actions per year across the industry. The supply chain disruption from a single nationwide retail recall of a product like Gas-X — stocked in virtually every pharmacy and mass retail chain in the country — creates consumer impact far beyond what the direct health risk might suggest.

ICH Q10 addresses this through the concept of a control strategy — a planned set of controls, derived from product and process understanding, that ensures process performance and product quality across the product lifecycle. A control strategy that doesn't account for known contamination routes in a specific manufacturing environment is incomplete by definition, regardless of how many other tests it includes.

Practical Steps for OTC Drug Manufacturers

If you're an OTC manufacturer reviewing your contamination prevention program in light of this recall, here is where I'd focus:

Step 1: Audit your cleaning validation coverage. Pull the cleaning validation studies for your highest-volume equipment. Check whether the validation covers the actual cleaning agents currently in use. Check whether swabbing locations reflect current equipment configuration. If there have been equipment modifications or cleaning agent changes in the past three years without revalidation, that's a gap worth addressing now rather than during an inspection.

Step 2: Map your lubrication points. For any piece of equipment where a lubricant is used near product-contact surfaces, document it explicitly. Confirm the lubricant is on your approved list. Verify that lubricant use is captured in equipment logs or batch records with enough specificity to support a contamination investigation if one ever becomes necessary.

Step 3: Review your release testing specifications. Do your finished product specifications include any analytical testing that would detect unexpected substances from the manufacturing process? If your QC release testing is limited to active ingredient identity, assay, dissolution, and appearance, you likely don't have the detection capability to catch a contamination event like this one before distribution.

Step 4: Check your change control program. Any change to a cleaning agent, a lubricant, or an equipment configuration should trigger a formal change control review that includes an explicit assessment of whether existing cleaning validation remains valid for the new conditions.

Step 5: Evaluate your batch record review process. Is the review genuinely analytical — are anomalies in cleaning logs or maintenance records actually investigated before a release decision is made? Or has it become primarily a signature collection exercise? The answer to that question usually predicts a quality system's exposure to events like this one.

This is exactly the kind of systems-level audit that Certify Consulting runs for OTC manufacturers as part of our GMP compliance consulting services. In over 200 client engagements, the pattern I keep seeing is that manufacturers find their gaps during an audit with a consultant, or they find them when FDA does. The former is considerably less expensive.

Frequently Asked Questions

What is the most common cause of cleaning agent contamination in pharmaceutical softgel manufacturing?

In my experience, it's usually a combination of two things: cleaning validation that wasn't updated when something changed (cleaning agent, equipment configuration, or production schedule) and lubrication points near product-contact surfaces that aren't specifically captured in the maintenance program. Either one alone can create a problem; both together make it likely at some point.

Does FDA require analytical testing for manufacturing residues in finished pharmaceutical products?

21 CFR 211.67 and FDA's Guide to Inspections of Cleaning Validation require that cleaning validation demonstrate residue removal to acceptable limits using validated analytical methods. However, release specifications for finished products don't always include lot-by-lot residue testing — the expectation is that a rigorous cleaning validation substitutes for it. That means if the cleaning validation has gaps, there may be no safety net at the finished product release stage.

What should an OTC manufacturer do if they discover potential cleaning agent contamination in a finished lot?

The lot should be immediately quarantined and a formal deviation investigation opened under the quality management system. The investigation should trace the contamination to its source using batch records, equipment logs, and environmental monitoring data. FDA notification and a market action decision — recall, market withdrawal, or other disposition — follow the investigation findings. Acting quickly and transparently is both the right thing to do and what FDA's enforcement posture consistently rewards compared to delayed action.

How often should cleaning validation studies be revalidated?

FDA doesn't specify a fixed revalidation interval, but the expectation is that cleaning validation remains current and applicable to actual production conditions. Clear triggers for revalidation include: changes to cleaning agents or procedures, changes to equipment configuration, introduction of new products that alter the worst-case profile, and periodic review as part of the annual product review. Most robust quality systems I've seen revalidate at least every three years under normal circumstances, and immediately upon any of the above triggers.

Which specific regulations govern contamination prevention in OTC drug manufacturing?

The primary framework is 21 CFR Part 211 (cGMP for Finished Pharmaceuticals), with 21 CFR 211.67 (equipment cleaning and maintenance), 21 CFR 211.68 (automatic and mechanical equipment), and 21 CFR 211.192 (production record review) being the most directly applicable. FDA's 2011 Process Validation Guidance and FDA's Guide to Inspections of Cleaning Validation provide the technical expectations. ICH Q9 (Quality Risk Management) and ICH Q10 (Pharmaceutical Quality System) offer the broader quality system framework within which contamination prevention controls should be embedded.

A contamination event of this kind is almost always preventable. The quality systems that prevent it aren't exotic — they're the same systems that 21 CFR Part 211 has required for decades. The question is whether those systems are genuinely functioning or just documented. If you want an outside perspective on where your contamination prevention controls actually stand, reach out to Certify Consulting. Our team has guided 200+ manufacturers through exactly this kind of audit — and maintained a 100% first-time audit pass rate doing it.

Last updated: 2026-06-16