What are pharmaceutical excipients?

They are classified by the functions they perform in a pharmaceutical dosage form. Principal excipient classifications (functions) are the following:
Binders
Disintegrants
Fillers (diluents)
Lubricants
Glidants (flow enhancers)
Compression aids
Colors
Sweeteners
Preservatives
Suspensing/dispersing agents
Film formers/coatings
Flavors
3. Why are excipients important in a drug product?For many reasons. Some, for example, comprise the product's delivery system. These transport the active drug to the site in the body where the drug is intended to exert its action. Others will keep the drug from being released too early in the assimilation process in places where it could damage tender tissue and create gastric irritation or stomach upset. Others help the drug to disintegrate into particles small enough to reach the blood stream more quickly and still others protect the product's stability so it will be at maximum effectiveness at time of use. In addition, some excipients are used to aid the identification of a drug product. Last, but not least, some excipients are used simply to make the product taste and look better. This improves patient compliance, especially in children. Although technically "inactive" from a therapeutic sense, pharmaceutical excipients are critical and essential components of a modern drug product. In many products, excipients make up the bulk of the total dosage form