The requirements for the material of cleaning validation swabs are as follows:

Low residual organic matter

• Background: The key to cleaning validation lies in accurately detecting the residual organic matter on the wiped surface. If the swab itself contains a high level of organic matter, it will interfere with the detection results and lead to misjudgment.
• Requirement: The material of the swab should have extremely low organic matter content, such as using purified cotton or synthetic fibers that have been specially treated, and strictly controlling possible organic impurities introduced during the production process to ensure that it will not significantly interfere with the detection results itself.

Good water absorption and release properties

• Background: During the wiping process, the swab needs to be able to quickly and effectively absorb the residual substances on the wiped surface, and in the subsequent detection and analysis, it can fully release the absorbed substances for accurate measurement.
• Requirement: The material should have a good fiber structure, such as having a certain porosity and specific surface area. For example, high-quality polyester fiber and cellulose mixed materials can quickly absorb liquid residues and be fully released in an appropriate solvent to ensure the integrity and representativeness of the detection sample.

Not easy to shed fibers

• Background: If the swab is prone to shedding fibers during use, the shed fibers may remain on the wiped surface, causing it to be misjudged as a pollutant on the equipment surface, and it may also affect the accuracy of the detection instrument.
• Requirement: The material should have sufficient strength and fiber binding force, such as using fibers that have been specially woven or bonded, to ensure that the fibers will not easily shed during the wiping process, ensuring the reliability of the detection results and the cleanliness of the equipment.

Chemical compatibility

• Background: In the cleaning validation process, various chemical reagents may be used for wiping or extracting and analyzing the residual substances on the swab, and the material of the swab needs to have good compatibility with these chemical reagents.
• Requirement: The material should have stable chemical properties and will not react or physically adsorb with common cleaning solvents and extraction reagents. For example, swabs with a polytetrafluoroethylene coating can remain stable when in contact with organic solvents, acids, alkalis and other chemical substances without affecting the detection process and results.

No biological activity

• Background: In some cleaning validation scenarios with strict requirements for microbial control, such as in the production of pharmaceuticals and biological products, the material of the swab should not contain any substances that may breed microorganisms or have biological activity, so as not to affect the accuracy of the cleaning validation and the quality of the product.
• Requirement: The material should be strictly sterilized, such as using gamma-ray sterilization or ethylene oxide sterilization to ensure that it is sterile and has no biological activity, and at the same time has good anti-microbial contamination performance during storage and use.

Dimensional and shape stability

• Background: In order to ensure the effective wiping of equipment surfaces of different shapes and sizes, the swab needs to have an appropriate size and shape, and be able to maintain shape stability during use, not easily deformed or damaged.
• Requirement: A reasonable size and shape should be designed according to actual usage requirements, such as long-handled, pointed or flat-headed swabs to meet the wiping requirements of different parts, and the material should have a certain degree of flexibility and rigidity to make it able to fit the surface during wiping and maintain shape stability at the same time.

Low static electricity generation

• Background: In some cleaning validation environments sensitive to static electricity, such as electronic component production workshops, static electricity may adsorb impurities such as dust, resulting in inaccurate detection results and even causing damage to equipment and products.
• Requirement: The material should have good anti-static performance, which can be achieved by adding anti-static agents or using special surface treatment techniques. For example, adding anti-static materials such as carbon nanotubes in polyester fibers to reduce or eliminate the generation of static electricity to ensure the accuracy and safety of the cleaning validation.