Excipient

Any component of a drug product other than the active ingredient, such as buffers, stabilizers, tonicity agents, surfactants and bulking agents. Many excipients used in Japan must meet the Japanese Pharmacopoeia or Japan's separate standards for pharmaceutical excipients, and an excipient with no previous use in Japan needs supporting data. Excipients can bring impurities into the product, for example elemental impurities from mineral-derived materials or peroxides from polysorbates, so supplier qualification and specifications matter as much as for active ingredients.