USING USP REFERENCE STANDARDS
Official Reference Standards
USP Reference Standards are required for use in pharmacopeial
assays and tests in the official standards publication, the United
States Pharmacopeia–National Formulary (USP–NF). USP
Reference Standards help to ensure compliance with the official,
FDA-enforceable quality requirements in the USP–NF. The
Reference Standards also lend themselves to many other
applications, including measurements required to obtain accurate
and reproducible results in modern chromatographic and
spectrophotometric methods.
The distribution of controlled substances is subject to the
regulations and licensing provisions of the Drug Enforcement
Administration of the U.S. Department of Justice.
USP also collaborates with the World Health Organization in
its program to provide international biological standards and
chemical reference materials for antibiotics, biologicals, and
chemotherapeutic agents. Some USP Reference Standards
are standardized in terms of the corresponding international
standards.
Rigorous Testing and Quality Control
USP Reference Standards are selected for their high purity,
critical characteristics, and suitability for the intended purpose.
Unless a USP Reference Standard label states a specific
potency or content, the USP Reference Standard is taken as
being 100.0% pure for the USP purposes for which it is provided. As a service to our customers, labeled purity values for
Reference Standards and Authentic Substances released after
January 1, 2004, are listed in this catalog. See p. 19 for an
explanation of how the values are calculated.
Proper Use of USP Reference Standards
USP Reference Standards are provided primarily for quality
control use in conducting the pharmacopeial assays and tests
described in the USP–NF. Neither Reference Standards nor
Authentic Substances are intended for use as drugs, dietary
supplements, or medical devices.
To serve its intended purpose, each USP Reference Standard
must be properly stored, handled, and used. Users of USP
Reference Standards should refer to General Chapter < 11>
in the USP–NF.
Heterogeneous substances of natural origin are also designated
“Reference Standards” where needed. Usually these are the
counterparts of international standards.
USP Reference Standards are established through a process
of rigorous testing, evaluation, and quality control. They are
independently tested in three or more laboratories—USP,
FDA, and industrial laboratories throughout the world. The
Reference Standards are released under the authority of USP’s
Board of Trustees, on the recommendation of the USP Reference
Standards Expert Committee, which approves selection and
suitability of each lot.
Reference Standards Categories
USP offers more than 2,000 Reference Standards for
pharmaceuticals, excipients, and dietary supplements. On pages
37– 110 of this catalog, you’ll find a full list of available USP
and NF Reference Standards, with information updated through
February 2008. The list includes
• Reference Standards required by the current official edition
of the USP–NF.
• Reference Standards not required in the current USP–NF,
but for which sufficient demand remains.
• Reference Standards specified in the current edition of the
Food Chemicals Codex.
• Authentic Substances—highly purified samples of
chemicals, including substances of abuse, required by
analytical, clinical, pharmaceutical, and research laboratories.
Listing and directions in the USP–NF
• Refer to the list of revisions, additions, and deletions of
individual USP Reference Standards in USP 31–NF 26.
Individual USP or NF monographs specify the USP
Reference Standard(s) required for assay and test procedures. USP 31–NF 26 General Chapter < 11> USP
Reference Standards provides additional information and
instructions for proper use and storage. Note that if specific
instructions for use appearing on the label of a USP
Reference Standard differ from the instructions in Chapter
< 11>, the instructions on the label take precedence.
• Consult the cumulative updates to Reference Standards
information provided in USP–NF Supplements and
also in USP–NF Interim Revision Announcements,
which are published in USP’s bimonthly journal,
Pharmacopeial Forum.
Suitability for use
• Users must ascertain that the Reference Standards they
are using are from an official lot.
• Users must determine the suitability of Reference
Standards for applications and uses not in the USP–NF.
