Structured Product Labeling (SPL)

Key facts

Standard owner

HL7 International; adopted by FDA

Format

XML documents with coded label sections and product data elements

Versioning

Set ID stays constant; version number increases with each revision

Used for

Labels, establishment registration, drug listing and labeler codes

Public distribution

DailyMed, run by the National Library of Medicine

What is Structured Product Labeling?

Structured Product Labeling is a machine-readable way to package a drug label. Instead of a PDF, the company submits an XML document that carries the full label text, split into sections identified by LOINC codes, plus structured data about each product the label covers.

The Food and Drug Administration (FDA) requires SPL for the content of labeling in drug applications and for drug establishment registration and drug listing. The National Library of Medicine (NLM) publishes the resulting documents on DailyMed, the main public source for current labels.

SPL is not limited to FDA-approved prescription drugs. The same standard carries over-the-counter Drug Facts labels, animal drug labels and listings for products marketed without FDA approval, so a document on DailyMed is not evidence that FDA approved the product.

How an SPL document is structured

Each SPL file combines narrative label content with coded data. The main parts are:

The set ID is the stable key. A label revision produces a new document ID and a higher version number under the same set ID.

• Document identifiers: a document ID for the specific file, a set ID shared by every version of the same label, and a version number.
• Label sections: indications, dosage, warnings and other sections, each tagged with a LOINC section code.
• Product data elements: proprietary name, active and inactive ingredients with FDA Unique Ingredient Identifiers (UNII), strength, dosage form and route of administration.
• Packaging: the NDC package codes and package descriptions covered by the label.
• Regulatory data: marketing category (such as NDA, ANDA, BLA or OTC monograph), application number, marketing dates and labeler.

Why SPL matters

SPL is the practical backbone of U.S. drug reference data:

• RxNorm draws on DailyMed SPL data, and the FDA NDC Directory and openFDA drug label data are built from SPL submissions.
• The coded application number and marketing category separate brand, generic and unapproved products without parsing text.
• Comparing successive versions under one set ID shows when a warning, indication or package was added.
• UNII codes and NDCs in the file let analysts join labels to pricing files such as NADAC, to recall notices and to claims data.

Limitations of SPL data

Listing SPLs are prepared by the companies themselves, and FDA does not verify all listing information before it is published, so errors and outdated listings occur. Repackagers and relabelers publish their own SPLs for the same underlying product, so a count of labels overstates the number of distinct drugs.