The tablet coating is the most significant procedure in the pharmaceutical industry, accounting for the last single-unit operation in which the tablets features can be modified. Said modification can be the result of either the application of a color coating, an isolation ensuring the stability of the components during the shelf life, a gastric acids resistant coating avoiding the degradation of acid sensitive actives, or a coating acting as a modulator of the active ingredient release. The coating can also be used as a procedure for the dosing of Active Pharmaceutical Ingredients (APIS) (quantitative coating).
All these possibilities can be effectively achieved only through a system or a film coating machine especially designed, and precisely implemented and customized.
BASICS
The tablet coating is the process of applying a suspension or solution, containing the components needed for the coating formation, on a moving bed of tablets, keeping a constant temperature in the bed. This constant temperature implies a dynamic balance, where the solvent of the applied liquid is at the same time evaporated and eliminated by extraction.
In practice, this balance is achieved by adjusting the following 5 critical variables of the process:
