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Upcoming Changes to USP's Description and Relative Solubility Reference Table

Type of Posting: Notice of Intent to Revise
Posting Date: 24-Jun-22

In accordance with the Rules and Procedures of the Council of Experts, this is to provide notice that USP Headquarters intends to revise the Description and Relative Solubility of USP and NF Articles Reference Table. 

History and Evaluation
Prior to 1980, USP monographs included prescription information (such as therapeutic category, usual dose and dose range, usual pediatric doses, dispensing information), and description and solubility, in addition to the analytical procedures and acceptance criteria. In USP 20–NF 15, USP removed the prescription information from the USP-NF. As stated in the Preface to USP 20, this change reflected “the continuing trend away from reliance on subjective criteria, however useful they may be from the standpoint of information, and toward precision and specificity in standards”.  The description and solubility information was retained, but moved from individual monographs into the Description and Relative Solubility of USP and NF Articles Reference Table.

As stated in the General Notices 5.30 Description and Solubility, the information provided in the Reference Table does not constitute a requirement: “The reference table merely denotes the properties of articles that comply with monograph standards. The reference table is intended primarily for those who use, prepare, and dispense drugs and/or related articles. Although the information provided in monographs and the information in the reference table may indirectly assist in the preliminary evaluation of an article, it is not intended to serve as a standard or test for purity.” Please also see a clarification provided under Identifying Official Text - FAQs, where Reference Tables are listed among the sections of the USP–NF which contain informational official text intended to aid compendial users, but do not state requirements with which users must comply. 

USP recently performed an analysis of over 2000 entries currently listed in the Reference Table to assess the value of the information provided. It was found that description and solubility information for many articles is readily available from other sources, reducing the value of USP recreating and maintaining this information separately. 

For drugs substances, the description and solubility information is typically available as a part of the FDA-approved labels of the products, in the ‘Description” section of the Drug label Information. FDA-approved labels are available at several sources, including the DailyMed searchable database (provided by National Library of Medicines) and Prescription Drug Labeling Resources (provided by the FDA). The information submitted by monograph sponsors for inclusion in the Reference Table is usually based on the Description section of the FDA-approved label. These resources are free for users and employ the same terminology for approximate solubility information as in General Notices 5.30, Description and Solubility

Next Steps
In USP-NF 2023 Issue 1, publishing on November 1, 2022, USP is planning to start the process of updating the Reference Table. USP plans to remove all entries pertaining to omitted monographs or those with no monograph association from the Reference Table. A list of entries planned for deletion can be found here.

Beginning with Pharmacopeial Forum 48(6) [Nov-Dec 2022], USP is planning to further revise the Reference Table to remove the entries for drug substances and legacy entries for drug products. Because there are no external sources of information for Excipients and Dietary Ingredients which are comparable to the sources of D&S information in FDA-approved labels, USP will continue to update and publish description and solubility information for these types of substances at this time. The updated table is targeted to appear in USP-NF 2024 Issue 1 with an official date of May 1, 2024.

The link to the list of deleted entries for drug substances and products is planned for posting in the PF Briefing. In preparation for this change and to ease the transition, when the description and solubility information is provided by a sponsor for new drug substance monograph proposals, it may be considered for inclusion in the monograph Briefing.

USP plans to update the Introduction section of the Reference Table to outline the new approach and include external links to where description and solubility information for drug substances can be obtained from non-USP sources. After the revision becomes official, all legacy description and solubility information can still be accessed in the USP-NF Online by viewing the “Older Versions” of this document. 

Should you have any questions, please contact Sujatha Ramakrishna, Senior Principal Scientist (