When Did USP and NF Merge? The 1975 Consolidation Explained

October 14, 2025 •

2 min read

The United States Pharmacopeia (USP) officially purchased the National Formulary (NF) on January 2, 1975, consolidating two separate compendia into a single, comprehensive volume for drug standards. This pivotal moment in pharmaceutical history combined the standards for both finished drug products and excipients into one authoritative resource.

Quick Summary

The United States Pharmacopeia acquired the National Formulary from the American Pharmaceutical Association in 1975, combining the separate publications into a unified compendium for drug and excipient standards.

Key Points

Official Merger Date: The United States Pharmacopeia (USP) purchased the National Formulary (NF) on January 2, 1975, from the American Pharmaceutical Association (APhA).
Pre-Merger Distinction: The USP, established in 1820, set standards for finished drug products, while the NF, created in 1888, covered excipients and unofficial preparations.
Rationale for Consolidation: The merger aimed to consolidate drug and ingredient standards into a single, comprehensive volume, improving efficiency and usability.
Federal Enforcement: Both compendia's standards were legally recognized by the U.S. Food and Drugs Act of 1906 and are enforced by the FDA today.
Unified Publication: The combined publication, USP–NF, now serves as the primary resource for quality standards in the pharmaceutical industry worldwide.
Future Transition: The USP-NF is transitioning to a bimonthly online publication model, effective July 2025, to provide more frequent updates.

A History of Separate Compendia

Before the 1975 merger, the United States Pharmacopeia (USP) and the National Formulary (NF) were distinct entities with different, yet complementary, roles in setting pharmaceutical standards. Founded in 1820 by physicians, the USP focused on creating uniform standards for drug substances and finished drug products. In 1888, the American Pharmaceutical Association (APhA) established the NF to provide standards for unofficial preparations and excipients. Both were recognized under the Federal Food and Drugs Act of 1906, which gave their standards legal weight, a status further reinforced by the Federal Food, Drug, and Cosmetic Act of 1938.

The Path to Consolidation

By the 1960s, the pharmaceutical landscape had evolved, diminishing the functional differences between the two publications. This led to discussions about a merger to address the inefficiency of maintaining separate references. In 1973, negotiations between the US Pharmacopeial Convention (USPC) and the APhA began. These discussions resulted in the USP purchasing the NF and the Drug Standards Laboratory from the APhA, with the official transaction occurring on January 2, 1975.

The Creation of the USP-NF

Following the 1975 acquisition, the USP combined the two publications into the single USP–NF. This consolidation aimed to simplify reference materials for the pharmaceutical industry. While unified, the USP–NF initially maintained distinct sections for USP (drug substances, dosage forms) and NF (excipients, other products) content.

Reasons for the USP-NF Merger:

Consolidation: Unified standards into one comprehensive reference.
Efficiency: Streamlined standards-setting by combining efforts.
Comprehensiveness: Provided a holistic approach to quality, covering active and inactive ingredients.
Legal Authority: Strengthened the authority of standards enforced by the FDA.

Comparison: USP vs. NF (Pre-1975)


Feature	United States Pharmacopeia (USP)	National Formulary (NF)
Established	1820	1888
Founding Body	Group of physicians and pharmacists	American Pharmaceutical Association (APhA)
Primary Focus	Standards for drug substances and dosage forms (active ingredients)	Standards for excipients, botanicals, and unofficial preparations (inactive ingredients)
Legal Status	Legally recognized under federal law since 1906	Also legally recognized under federal law since 1906
Acquired by USP	N/A	1975

Modern Developments Since the Merger

Since 1975, the USP-NF has continued to evolve. In 2006, the USP acquired the Food Chemicals Codex (FCC), integrating food ingredient standards into the USP–NF. Efforts are ongoing to consolidate all standards under the 'USP' designation. The publication has also moved towards online-only bimonthly updates to accelerate the release of official content.

Conclusion

The merger of the USP and NF on January 2, 1975, was a significant event that improved pharmaceutical quality control in the United States. This consolidation created a more efficient and comprehensive resource for drug standards, ultimately enhancing public health and patient safety.

Visit the official USP website for more information on the history of pharmaceutical standards.

Frequently Asked Questions

Before their 1975 merger, the USP set standards for active drug substances and finished products, while the NF provided standards for excipients and other inactive ingredients.

The merger was driven by the desire to consolidate the two separate but related compendia into a single, comprehensive reference, improving efficiency and creating a more holistic standard for pharmaceutical quality.

The USP-NF is the combined publication of the United States Pharmacopeia and the National Formulary. It is a single resource containing quality standards for medicines, drug substances, excipients, and other therapeutic products.

Yes, the standards published in the USP–NF are enforceable by the U.S. Food and Drug Administration (FDA) for medicines manufactured and marketed in the United States.

The National Formulary (NF) was originally established in 1888 by the American Pharmaceutical Association (APhA).

The National Formulary was based on the New York and Brooklyn Formulary (NYBF). Efforts led by New York pharmacists in 1883 laid the groundwork for its creation.

No, after the 1975 merger, the USP and NF were published under the same cover as the USP–NF. The separate sections for USP and NF content were maintained, but they were bound together in one volume.

The 1906 Act gave the standards in both the USP and NF legal recognition, stating that drugs would be considered 'adulterated' if they did not meet the standards outlined in these official compendia.