Pharmaceutical excipients are substances other than the pharmacologically active drug or prodrug which are included in the manufacturing process or are contained in a finished pharmaceutical product dosage form.

In addition to transporting the active drug to the site in the body where the drug is intended to exert its action, excipients play an important part in the manufacturing process. They may also be important for keeping 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.