During a pharmaceutical contamination control investigation, a manufacturer discovered that a routine cleanroom consumable was contributing to elevated airborne particle counts. Testing showed that swabs used during routine equipment cleaning released particles into the controlled environment.
The manufacturer replaced the existing product with Foamtec’s CleanWIPE® Cleanroom Foam Swabs. Manufactured using automated fabrication and inspection processes, the swabs were selected for their low particle generation, solvent compatibility, and consistent construction. No other part of the established cleaning process was changed during the evaluation.
Following the change, the manufacturer recorded a 30% reduction in airborne particle counts over a 12-week evaluation period covering multiple comparable production cycles.
The Challenge: Particle Counts Remained Elevated
Environmental monitoring showed that airborne particle levels remained higher than expected despite established contamination controls and validated cleaning procedures. Repeating the same process was unlikely to explain why the counts persisted, so the quality team expanded its investigation.
In the pharmaceutical industry, contamination can come from personnel, raw materials, packaging materials, processing equipment, air-handling systems, cleaning agents, and tools used during cleaning.
EU GMP Annex 1 addresses these potential sources as part of a comprehensive strategy for controlling contamination, including microbial, particulate, endotoxin, and pyrogen risks.
The manufacturer also needed to consider how particles introduced during equipment cleaning could affect the controlled environment, product quality, and the reliability of subsequent monitoring across the entire facility, not just the immediate cleaning area.
The Investigation Expanded Beyond Common Sources
The quality team reviewed environmental monitoring trends and compared the materials involved in routine cleaning. Testing indicated that the existing swabs released particles during use.
This created a counterproductive situation: a tool intended to remove contamination was potentially introducing particles into the same environment it was meant to help control.
The team also considered particle size, monitoring location, production conditions, and the timing of each cleaning event when reviewing the environmental data. These factors helped distinguish a recurring material-related trend from an isolated particle excursion.
How the Manufacturer Evaluated the Change
The manufacturer compared environmental monitoring data collected before and after the CleanWIPE® swabs were introduced. The same particle-counting method remained in place throughout the 12-week evaluation period.
A Consistent Before-and-After Comparison
The evaluation followed four steps:
- Establish the baseline. The team reviewed particle-count data from the existing cleaning process.
- Introduce the new swabs. CleanWIPE® swabs replaced the previous product without changing the broader cleaning procedure.
- Continue environmental monitoring. The facility maintained the same monitoring locations, particle-counting method, and comparable production conditions.
- Review the outcomes. The team compared particle trends, cleaning-validation performance, and contamination-related reject data.
Maintaining consistent measurement and sampling procedures made the before-and-after results easier to interpret. The evaluation also considered the defined particle size ranges and monitoring conditions used by the facility.
The manufacturer documented the material change, monitoring method, evaluation period, acceptance criteria, and resulting observations as part of its broader cleaning validation program, supporting regulatory compliance throughout the process.
The FDA’s Q7 Good Manufacturing Practice Guidance addresses cleaning procedures, validation protocols, sampling methods, acceptable cleaning levels, and analytical methods used in the manufacture of active pharmaceutical ingredients.
The Results After 12 Weeks
Following the swab change, the manufacturer recorded a 30% reduction in airborne particle counts across the evaluation period.
The manufacturer also observed more consistent cleaning-validation performance and fewer contamination-related rejects. These improvements reduced the operational demands associated with investigations, repeat cleaning, repeat testing, and product-disposition activities.
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| Measured area | Result during the evaluation period |
|---|---|
| Airborne particle counts | Decreased by 30% |
| Cleaning-validation performance | Became more consistent |
| Contamination-related rejects | Decreased |
| Associated investigation and rework demands | Reduced |
The results provided documented evidence that the cleaning swab was a meaningful process variable. They did not establish that every particle excursion came from the previous swab or eliminate the need to monitor other contamination sources.
Why a Small Process Material Made a Measurable Difference
When a cleaning tool sheds particles, it can undermine the process it is meant to support. It may also complicate the validation process by introducing an additional contamination source that must be distinguished from equipment residue, environmental particles, and material transferred from another production stage.
In this case, changing the swab allowed the manufacturer to address one recurring variable without altering the wider cleaning procedure. The improvement reinforced four broader contamination-control principles:
- Routine consumables should be evaluated as potential contamination sources.
- Cross contamination can involve particles and fibers as well as product residues.
- Material changes should be introduced and measured under consistent conditions.
- Product selection should reflect the surface, solvent, process, and cleanroom requirements.
For manufacturers that employ semi-automatic cleaning equipment — as well as those running closed systems, large systems, or dedicated equipment that is not routinely disassembled — the same principle applies. Such systems still depend on the cleanliness of every consumable that contacts a product surface.
Connecting Particle Control With Cleaning Validation
A cleaning validation protocol should define the equipment and surfaces included, cleaning method, sampling method and procedures — whether direct sampling, swab-based, or rinse-based — analytical method, acceptance criteria, and documentation requirements.
Depending on the application, the validation process may assess:
- Residues from active pharmaceutical ingredients
- Cleaning agents and other chemical residues
- Microbial or endotoxin concerns
- Particles, fibers, and foreign material
- Possible carryover between drug products
- Cross contamination risks within shared equipment or areas
The final validation report should bring together the approved protocol, deviations, analytical results, observations, acceptance decisions against predetermined specifications, and documented evidence supporting the conclusion.
What Other Pharmaceutical Manufacturers Can Review
When particle levels remain elevated after routine cleaning, repeating the same procedure may not identify the source. The investigation should also consider whether a material, surface, or handling practice is introducing or redistributing contamination.
A focused review can include:
- Swabs and wipes: Evaluate particle generation, fiber shedding, residue, and construction consistency.
- Cleaning agents: Confirm compatibility with equipment surfaces and cleaning materials.
- Equipment surfaces: Look for retained particles, chemical residues, damage, or difficult-to-reach areas.
- Cleaning technique: Determine whether the process removes contamination or transfers it elsewhere.
- Material handling and personnel flow : Review how cleaning consumables, raw materials, and packaging materials are stored, introduced, used, and discarded, and how personnel movement through the area may contribute to contamination.
- Environmental monitoring trends: Compare results by particle size, location, production stage, cleaning event, and material change.
- Sampling procedures: Confirm that the method, sampling location, and recovery technique are defined and consistently followed.
- Written procedures: Verify that cleaning tools, use techniques, and replacement frequencies are clearly documented.
- Change controls: Record the reason for the material change, evaluation method, acceptance criteria, and results.
- Cross contamination controls: Consider whether tools or materials can transfer particles or residues between surfaces, equipment, products, or processing areas.
This approach can help narrow the investigation to specific process variables instead of treating every excursion as a general cleaning failure.
Questions About Cleanroom Swab Selection
What Should Pharmaceutical Manufacturers Look for in a Cleanroom Swab?
A cleanroom swab should provide low particle generation, controlled cleanliness, consistent construction, suitable tip geometry, and compatibility with the cleaning agent and equipment surface. For sampling applications specifically, the swab and analytical method together must be sensitive enough to detect residuals at or below the facility’s established detection limit.
The appropriate product depends on the application. A swab used for equipment cleaning may require different performance characteristics from one used as part of validated sampling procedures.
How Can a Manufacturer Evaluate a Swab Change?
Establish a documented baseline and compare environmental or surface-cleanliness data before and after introducing the new product. Keep other relevant process conditions as consistent as practical during the evaluation.
The assessment should define monitoring locations, particle size ranges, acceptance criteria, evaluation period, and the number of comparable production or cleaning cycles. Results should be reviewed within the facility’s change-control and validation program.
Can a Swab Change Reduce Cross Contamination?
A lower-shedding swab can help reduce one potential source of particle transfer. However, controlling cross contamination requires a broader strategy that may include equipment design, personnel practices, material movement, cleaning methods, air controls, and separation between manufacturing activities.
Swab selection should therefore be treated as one control within the pharmaceutical facility’s complete contamination-control system.
Does Particle Reduction Prove That Equipment Is Free of Product Residue?
No. Environmental particle data and chemical-residue data answer different questions. Particle reduction shows a change in measured airborne particulate levels, while residue testing evaluates whether the cleaning process has removed product or cleaning-agent residues to an established limit.
Both forms of evidence may be important, but one does not replace the other.
Why Should Cleaning Consumables Be Included in Particle Investigations?
Swabs and wipes come into direct contact with equipment and controlled surfaces. If they shed particles, fibers, or residue, they can introduce contamination while appearing to support the cleaning process.
Including these materials in root-cause investigations can reveal variables that may be overlooked when the investigation focuses only on personnel, equipment, and air-handling systems.
When Should a Cleanroom Swab Be Replaced?
A swab should be replaced after its defined cleaning pass or when the tip has collected visible contamination. Reusing a contaminated swab can redistribute particles or residue to another part of the surface.
Replacement frequency should be specified in the pharmaceutical facility’s written cleaning procedure and supported by the requirements of the application.
From One Overlooked Variable to Better Particle Control
For this manufacturer, the improvement came from looking beyond the most obvious contamination sources.
The manufacturer recorded a 30% reduction in airborne particle counts without redesigning the wider manufacturing system. The case demonstrates how evaluating materials used during routine cleaning can strengthen pharmaceutical contamination control, protect product quality, and support more reliable process investigations.
Foamtec International supports pharmaceutical manufacturers from Waco, Texas, with cleaning tools and contamination-control solutions for critical surfaces, particles, fibers, residues, and cross contamination risks.