what is the difference between usp and nf
United States Pharmacopeia The United States Pharmacopeia (USP) is a pharmacopeia (compendium of drug information) for the United States published annually by the United States Pharmacopeial Convention (usually also called the USP), a nonprofit organization that owns the trademark and copyright. The USP is published in a combined volume with the National Formulary (a formulary) as the USP-NF.[2] If a drug ingredient or drug product has an applicable USP quality standard (in the form of a USP-NF monograph), it must conform in order to use the designation "USP" or "NF." Drugs subject to USP standards include both human drugs (prescription, over-the-counter, or otherwise), as well as animal drugs. USP-NF standards also have a role in U.S. federal law; a drug or drug ingredient with a name recognized in USP-NF is deemed adulterated if it does not satisfy compendial standards for strength, quality or purity. USP also sets standards for dietary supplements, and food ingredients (as part of the Food Chemicals Codex). USP has no role in enforcing its standards; enforcement is the responsibility of Food and Drug Administration (FDA) and other government authorities in the U.S. and elsewhere.
United States Postal Service The United States Postal Service (USPS; also known as the Post Office, U.S. Mail, or Postal Service) is an independent agency of the United States federal government responsible for providing postal service in the United States, including its insular areas and associated states. It is one of the few government agencies explicitly authorized by the United States Constitution.