Choosing the Correct Swab for Cleaning Validation
During the manufacture of pharmaceutical and biotechnology products, care must be taken to ensure that these products are not contaminated either by the previous manufacturing run or by the cleaning process itself.
During the manufacture of pharmaceutical and biotechnology products, care must be taken to
ensure that these products are not contaminated either by the previous manufacturing run or by the cleaning process itself. The cleaning process can be validated by sampling various parts of the manufacturing equipment and analyzing the sampling material for contaminants.
Typically, swabs are used for sampling. Any product or cleaning residue can be eluted from
the swab and analyzed using standard analytical techniques such as high performance liquid
chromatography (HPLC) or gas chromatography. Recently, total organic carbon (TOC) has been
gaining favor as the analytical method of choice because it is a sensitive technique that will
measure all oxidizable carbon compounds, regardless of organic functional groups.
Three of the most important criteria for choosing a swab for cleaning validation include:
- Minimal Background— Background is the amount of contaminant on a swab measured by the analytical technique after testing has been performed according to the analytical protocol before sampling. Blank contribution from the swab must be minimal.
- High Recovery Rate— Recovery means the percentage of contaminant actually measured by the analytical technique when the swab is spiked with a known quantity of that species. Sixty-percent recovery rates are acceptable; however, higher recovery rates are desirable.
- Low Particle Generation—It is critical that the swabbing material leave the swabbed surface free from particles which would further contaminate the surface.