The Science Behind Coated Tablets & The Insight of Tablet Coating

Have you ever wonder why some of the tablets that prescribed by doctors or pharmacists are coated in various colors and some are just plain white tablets that are uncoated? How do you know that the tablets are coated or not?

It is usually stated in the original box or packaging material as well as the leaflet in the box of medicine whether the tablet is film-coated or not.

 

Another way to find out that the tablet is coated or not is by breaking the tablet into half and see whether there is a thin layer of film covering the surface of the tablet that you can peel off at times. The process which involves the application of thin (20-200µm), polymer-based coatings to an appropriate substrate such as tablets, capsules, pellets is known as film coating. 

Why some tablets need to be film-coated? 

There are many reasons on why pharmaceutical drug manufacturers coat their tablets and are listed in the table below:

For Processing	Improving packaging efficiency Less powdery Reducing cleaning time Reducing tablet breakage and chipping Prevention of cross contamination
For Marketing	Improving visual appearance of tablets Color for branding purposes and trademark
For Product Stability	Protecting the product from moisture, light, oxidation and/or the acidic environment of the stomach Can impart mechanical integrity, color and gloss of the tablets
For Functionality	Many film coating materials have functional properties which enable the creation of sustained or delayed (enteric) release dosage forms
For Consumer	For identity of the drugs Easing swallowability of the tablets Masking the bitter taste and objectionable odors

 Have you ever wonder how the tablets are film-coated?

This sequence of photographs exemplifies the typical film-coating process, where uniformity of coverage is poor in the early stages of the process, and gets progressively better as the process proceeds.

The short video below also illustrates how the tablets are film-coated in the coater machine.

The micro view of the coating process is illustrated in the diagram below.

To know more about the coating solutions, equipments and systems used to film-coat the tablets as well as the procedure and process involved in tablet coating, you can visit this link http://www.dipharma.com/TC_20050401_20.pdf