Pharmaceutical tablets are the most popular medicinal dosage used today. Each tablet is made up by a combination of active substances (the chemicals that produce pharmacological effect) and inactive substances (disintegrant, binder, lubricant, diluent – usually in the form of powder). The active and inactive substances are then compressed or molded into a solid. Then, depending on the manufacturer specifications, the tablets are either coated or uncoated.
To be effective, tablet coatings need to follow the fine contours of embossed logos or characters on tablets, they need to be stable and sturdy enough to survive handling of the tablet, and they must not cause the tablets to stick to each other during the coating process. Current tablets typically have a polysaccharide and polymer-based coating which include substances like pigments and plasticizers. The two most common types of table coatings are film coatings and sugar coating. Compared to sugar coatings, film coatings are less bulky, more durable, and are less time-consuming to prepare and apply. However, film coatings have more difficulty hiding tablet appearance.
Tablet coatings are essential for moisture protection, masking the taste of the ingredients, and making the tablets easier to swallow. More importantly, the tablet coating controls the location and the rate in which the drug is released.