Motivated by internal government recommendations, initiatives, and legal mandates, the US Food and Drug Administration released
structured product labeling (SPL)–related regulations for 21 CFR Parts 314 and 601. On Feb. 5, 2004, the agency provided an SPL draft guidance for industry entitled, Providing Regulatory Submissions in Electronic Format—Content of Labeling as recorded in the Federal Register (1) and announced acceptance of SPL applications on Sept. 24, 2004, in public docket number 92S-02512. The challenge was
to build an effective regulatory guidance system using more-flexible application tools than portable document format (PDF)
or Microsoft Word for the electronic maintenance of market applications such as human drugs and biologic content. At the forefront
of the research was Health Level Seven (HL7), a volunteer American National Standards Institute–accredited standards developing
organization that focuses on the development of specifications for the standardized maintenance of clinical and administrative
healthcare data. HL7 has defined a new data file definition called SPL, which is based on the Web standard extensible markup
language (XML). As of this month, FDA requires that all labeling content information for human prescription drugs be submitted
in SPL XML format. PDF format will no longer be accepted. So, what is XML and why is it important for SPL compliance?
XML and SPL applications
XML, an electronic file format supported by numerous software manufacturers and endorsed by the World Wide Web Consortium
(W3C) as an industry standard, enables practical solutions for electronic business transactions. Because it can be read by
multiple source applications and disseminated in a variety of formats, XML delivers the promise of "one version of the truth."
For example, the boxed warning information in an FDA-approved submission can be repurposed immediately as the content in the
next print run of an accordion-style printed insert that accompanies a physical product. The printing system can be readily
updated by the approved structured content in the SPL file.
Designed for large-scale electronic publishing and exchanging information on the Web, XML is a subset of standard generalized
markup language (SGML). XML development began in 1996 and was formally recommended by W3C in 1998 (3). XML is much like HTML
in its coding structure. They differ, however, in that XML was created to define and describe specific pieces of information
using user-defined custom tags and attributes, while HTML is limited by the use of predefined tags for visual representation
The XML standard provides a wide-open platform to create data structures and related data-storage elements. Custom designed
data definitions, data types, attributes, hierarchal relationships, and general taxonomy are collected in XML schemas. Once
created, XML tag elements defined in the schema can be used, as needed, to record the actual data values in the XML file.
FDA provides a large set of elements in a predefined SPL schema for representing labeling data. This SPL schema set is dedicated
to recording drug product information and has embedded coding values to support efficient computability for search and retrieval.
The SPL schema structure ensures that a uniform representation of the product data is maintained across all labels.
SPL XML applications can maintain all of the textual-based information, data elements, and images needed for drug approval,
including drug listing information. XML also can efficiently handle multimedia such as tables, images, and complex documents.
Pharmaceutical companies can expand the XML format into almost every branch of their businesses.
XML can integrate dissimilar operations by consistently exchanging standardized data. Because the content is kept separate
from the format, multiple application databases using XML can be distributed across many servers while maintaining the integrity
of the data. Likewise, documents can be viewed on various media with extensible stylesheet language (XSL) style sheets, which
allows different ways of presenting the labeling information, in accordance with the preferences of the targeted audience
without the need to reprogram or manipulate the information. XML supports both unicode and multilingual documents, thereby
facilitating the internationalization of complex data.