Manufacturers and consumers both like to see polished and shiny capsules. Capsules covered in dust from the drug product formulation look unappealing and may have an unpleasant taste. The dust can also cause problems with bottling and blister packaging equipment and require excessive housekeeping in capsule-filling and packaging areas. Capsule polishers can eliminate these problems by cleaning the outside of the capsules as they exit the capsule filler.
Pharmaceutical manufacturers originally filled capsules manually and then wiped the capsules with a polishing cloth to physically remove any dust from the capsule's exterior. This was effective as long as the quantity of filled capsules was small. As suppliers developed machines to automate the capsule-filling process, production rates increased and manual polishing became too slow and labor intensive. To speed the process, manufacturers collected capsules in a pail from the filler and then dumped them into a coating pan and tumbled them with sodium chloride (polishing salt) until the capsule shells were polished. They then dumped the capsules from the coater onto a sifter to remove the salt. Although effective, this method was also time-consuming because it added another production step.
As capsule fillers increased in speed over the years, manufacturers needed a way to automate the capsule-polishing process in a way that could keep up with a capsule filler's speed. This led to the development of the brush-type capsule polisher.