Excipient

An excipient or inactive ingredient is a substance formulated alongside the active ingredient of a medication. They enhance the active ingredient's therapeutic properties; to facilitate drug absorption, to modify viscosity, to enhance solubility, to improve long-term stabilization (preventing denaturation and aggregation during the expected shelf life). During the manufacturing process, excipients can improve the handling of active substances and facilitate powder flow. The choice of excipients depends on factors such as the intended route of administration, the dosage form, and compatibility with the active ingredient.

Virtually all marketed drugs contain excipients, and final drug formulations commonly contain more excipient than active ingredient. Pharmaceutical regulations and standards mandate the identification and safety assessment of all ingredients in drugs, including their chemical decomposition products.