Coped below is the response provided by Antonio Hernandez-Cardoso, Senior Scientific Liaison at USP. I would suggest directing any further question on this matter directly to him at
AHC@usp.org.
The purpose of the USP General Chapter <631> Color and Achromicity is to provide well-controlled methods for the assessment of color and achromicity of uniform liquid samples. Currently it is referenced in 17 USP monographs and 35 NF monographs, under the section: "Specific Tests".
The "Description" statements pertaining to an article (formerly included in the individual monograph) are general in nature. The properties are not in themselves standards or tests for purity even though they may indirectly assist in the preliminary evaluation of the integrity of an article. Organoleptic characteristics are indicated in many instances because they may be useful and descriptive properties of substances. However, they are not meant to be applied as tests for identifying materials.
<631> contains "Matching Fluids" as Colorimetric Solutions for comparison prepared with Cobaltous Chloride (red), Ferric Chloride (yellow), and Cupric Sulfate (blue). Similar approach to other pharmacopeias. However, <631> is not harmonized with the chapter 2.2.2. described in the Eur.Ph. It is not possible to compare directly or to show equivalency between the color standards in both pharmacopeias. Recently USP has been working on a different approach to propose a new instrumental determination of color to be incorporated in the chapter <631>. The proposal is described in the Stimuli article titled: "Modernization of Color Measurement Methods in the USP–NF" published in the PF 44(4) [Jul-Aug, 2018], available online, free of charge at: www.usppf.com. On January 1, 2020 we published a proposal for a new instrumental procedure in <631> in PF 46(1) [Jan-Feb, 2020].
Finally, it is important to clarify the <631> is applicable when it is referenced in an official monograph or general chapter, as explained in the USP General Notices, under the title "3.10. Applicability of Standards". Other applications are out of the scope.
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Victor Pribluda
Senior International Regulatory Intelligence Manag
Rockville MD
United States
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Original Message:
Sent: 17-Jul-2020 07:41
From: Anonymous Member
Subject: USP color monograph
This message was posted by a user wishing to remain anonymous
Did anyone use USP monograph 631 for color description foe appearance of the product. I don't see standard colors like Red Blue Green in this panel like EP. For products with strong colors like Red ( blood derived) do we need to use the monograph in US?