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Applying glaze in a coating pan

Q: Can pharmaceutical glaze be applied to tablets in a Thomas "Accela Cota" coating pan? If so, what provisions would need to be in place?

A: Fred Rowley responds:

Pharmaceutical glaze, also known as shellac, is customarily applied by ladle in a nonperforated apple- or pear-shaped pan. It may also be applied using spray guns in an Accela Cota 48" pan if one understands the difference between the two types of pans.

The Accela Cota is totally perforated and therefore any alcohol-based shellac will dry at significantly faster rates than with the nonperforated pan. Because the air-assisted gun brings into play another factor, the operator needs to be aware of proper gun placement and sufficient atomizing air.

Knowing this, using the Accela Cota requires the operator/formulator to remember two important things:

1. At higher temperatures, the coating process will be quick and dry; and
   
   
2. You may wish to lower the processing temperature so that the alcohol does not flash off as fast and the process will be both more controllable and predictable.