Swab sampling is considered the most widely utilized cleaning validation sampling technique. It is also the crucial step in cleaning validation assessment.
The swabbing motion generally comprises several manual steps that can vary from colleague to colleague and is an inherently subjective activity. A rigorous training program in addition to a well-designed swabbing qualification program will enhance consistency in the execution of the swab sampling technique and hence improve confidence in the residual results obtained.
The following is an example of a swabbing procedure:
a) Place 5.0 mL of recovery solvent into a suitable capped container.
b) Thoroughly wet the swab tip with the recovery solvent and allow the excess liquid to drain back into the container. This can be achieved by quickly and lightly touching the swab tip to the inside of the container.
c) Press the swab tip firmly and evenly on the surface to be swabbed. d) Draw the swab across the surface of the substrate slowly and deliberately in a back and forth motion (back and forth is one stroke).
e) Cover the entire 25 cm2 area in seven to ten strokes.
f) Rotate the tip of the swab 180 degrees and complete steps (c to e) at an orientation perpendicular to the initial motion.
g) Cut the swab so that the tip is quantitatively captured in the container.
h) Immediately repeat steps (c to g) with a dry swab.
i) Cap the container and prepare the sample for analysis.
Resource Person: Md. Meshkat Sharif
