Hydroxyethyl Cellulose

Type of Posting: Notice of Adoption of Harmonized Standard

Posting Date: Sep–27–2019

Official Date: Aug–01–2020

Expert Committee: Excipient Monographs 2

Coordinating Pharmacopeia: European Pharmacopoeia

The new harmonized standard for Hydroxyethyl Cellulose has been approved by the Pharmacopeial Discussion Group (PDG) as described in its PDG sign-off cover sheet. Having reached Stage 4 of the PDG process, the Hydroxyethyl Cellulose monograph has been formally approved by the Excipient Monographs 2 Expert Committee in accordance with the Rules and Procedures of the Council of Experts.

Changes from the existing USP–NF monograph include:

  • In the beginning of the monograph, added the statement: "Portions of this monograph that are national USP text, and are not part of the harmonized text, are marked with symbols test symbol to specify this fact."
  • Definition
    • Revised to include the content limits for the hydroxyethoxy groups and use of suitable pH stabilizers.
  • Identification
    • Added a new test A with Infrared (IR) spectrophotometry using the attenuated transmission reflectance (ATR) technique according to the PDG sign-off document. 
    • Changed the original test A as test B, clarified the sample solution preparation procedure and revised the analysis from "heated to 60°" to "heat 10 mL of Sample solution to boiling". 
    • With the addition of IR, the original tests B and C were deleted.
  • Assay
    • A new assay test by capillary GC method is added. A suitable column is RTX-1, 0.53-mm × 30-m, 3-µm, G1 column from Restek. The retention time for internal standard (n-octane) is about 10 min.
    • Apparatus - local text to have more detailed description for the stakeholders.
  • Chlorides
    • New test is added.
  • Nitrates
    • New test is added.
  • Aldehydes
    • New test is added.
  • Residue on Ignition
    • Changed the current test to include the use of viscosity testing for Nitrates and Residue on Ignition to determine the appropriate acceptance criteria.
  • pH
    • Changed acceptance Criteria from "6.0 – 8.5" to "5.5 – 8.5".
  • Loss on Drying
    • Sample amount of 1.000 g was added.
  • Viscosity
    • Changed to use rotational methods, Viscosity-Rotational Methods <912>. This is a non-harmonized attribute. 
    • In addition, for the purpose of determining applicable limit for the tests of Nitrates and Residue on Ignition, added a separate harmonized viscosity testing procedure. 
  • Labeling
    • Included the statement of "The label states the name and concentration of any added pH-stabilizer." In addition, a correction from "average value" to "labeled value" was made to be consistent with the viscosity acceptance criteria.
  • Added USP Reference Standards section to include USP Hydroxyethyl Cellulose RS and USP Sodium Chloride RS.
  • Added test symbol symbols for Lead, Viscosity, Labeling and Package and Storage tests, because they are either non-harmonized attributes or local requirements for Hydroxyethyl Cellulose NF monograph. 
  • Additionally, the monograph has been edited to be consistent with the current USP style.

The Hydroxyethyl Cellulose monograph will be incorporated into USP-NF and become official from Aug. 1, 2020. 

Should you have any questions about the Hydroxyethyl Cellulose monograph, please contact Dr. Tong (Jenny) Liu (240-221-2072 or jyl@usp.org). For any questions about the PDG and its processes, please see the Pharmacopeial Harmonization website or contact Richard Lew at (240-221-2060 or rll@usp.org).