Solid oral dosage forms, including tablets and capsules, represent approximately 80% of all pharmaceutical preparations. These types of dosage forms dominate the marketplace because they deliver a constant controlled dosage of active drug, have excellent stability properties, are easily stored, are convenient to use and are available in a range of physical appearances.

　　The shape, size and color are all visual characteristics used to differentiate products, and the coloration of solid dosage forms is widespread, depending upon the physical properties of the product, the characteristics of the active ingredient and the geographic region in which the product is to be marketed.

　　There are a number of reasons to color capsules, including:

　　• Identification. To help pharmacists and patients on multi-dosage regimes. A patient will often refer to the color and shape of dosage form;

　　• Flavor perception. The patient's expectation of the flavor and color of a product is important; for example, consumers expect a cherry flavored lozenge to be red;

　　• Brand identification. Color offers the pharmaceutical manufacturer an easy route to brand identification in a highly competitive market;

　　• Quality perception. Color can be added to increase the aesthetic value of the product, thereby increasing the perception of quality;

　　• Counterfeit prevention. The development of unique colors for a particular active drug and the application of colored printing can help to reduce the risk of counterfeiting.