The purpose of the joint FDA/USP Substance Registration System (SRS) is to support health information technology initiatives by generating unique ingredient identifiers (UNIIs) for substances in drugs, biologics, foods, and devices. The UNII is a non- proprietary, free, unique, unambiguous, non semantic, alphanumeric identifier based on a substance’s molecular structure and/or descriptive information.

Prefix
unii
Links
Homepage
Contact
Missing Contact
Pattern for Local Unique Identifiers

Local identifiers in Unique Ingredient Identifier should match this regular expression:
^[A-Z0-9]+$

Example Local Unique Identifier
3G6A5W338E   Resolve
Pattern for CURIES

Compact URIs (CURIEs) constructed from Unique Ingredient Identifier should match this regular expression:
^unii:[A-Z0-9]+$

Example CURIE
unii:3G6A5W338E
Ontology

A summary of the relations in the Bioregistry schema can be found here.

In Collection
FHIR External Terminologies
Metaregistry Unique Ingredient Identifier

The metaregistry provides mappings between the Bioregistry and other registries. There are 5 mappings to external registries for this resource with 3 unique external prefixes.

Registry Name Registry Metaprefix External Prefix Curate
BioContext biocontext UNII
CHEMINF cheminf 000563
Identifiers.org Identifiers.org logo miriam unii
N2T Name-to-Thing logo n2t unii
Wikidata Wikidata Property logo wikidata P652
Providers

A provider turns a local unique identifiers from a resource into a URI. Many providers are also resolvable as URLs (i.e., they can be used in a web browser).

The local unique identifier 3G6A5W338E is used to demonstrate the providers available for Unique Ingredient Identifier. A guide for curating additional providers can be found here.

Name Metaprefix URI
Unique Ingredient Identifier unii https://precision.fda.gov/uniisearch/srs/unii/3G6A5W338E
Bioregistry bioregistry https://bioregistry.io/unii:3G6A5W338E
Identifiers.org miriam https://identifiers.org/unii:3G6A5W338E
Name-to-Thing n2t https://n2t.net/unii:3G6A5W338E
Extra Providers

Additional providers curated in the Bioregistry are listed here. These are typically inherited from Identifiers.org or Prefix Commons, and need extra curation.

Code Name URL
CURATOR_REVIEW UNII at U.S. Food and Drug Administration http://fdasis.nlm.nih.gov/srs/srsdirect.jsp?regno=3G6A5W338E