ABSTRACT
Almost all therapeutic products, including therapeutic products for human and veterinary use, include excipients-indeed, the total amount of excipients frequently used is greater than the amount of the active drug substance(s) in a dosage form. As with drug substances, excipients are derived from natural sources or are synthesized either chemically or by other means. They range from simple, usually highly characterized, organic, or inorganic molecules to highly complex materials that are difficult to fully characterize.
