Hydroxypropyl Cellulose

Type of Posting: Notice of Adoption of Harmonized Standard

Posting Date: 28-Feb-2014 (updated 27-Feb-2017*)

Official Date: 01–Dec–2014

Expert Committee: Monographs—Excipients

*Coordinating Pharmacopeia: USP

A harmonized standard for Hydroxypropyl Cellulose has been approved by the Pharmacopeial Discussion Group (PDG) as described in its PDG Stage 6 sign-off cover sheet. Having reached Stage 6 of the PDG process, the Hydroxypropyl Cellulose monograph has been formally approved by the USP Monographs—Excipients Expert Committee in accordance with the Rules and Procedures of the 2010–2015 Council of Experts.

Changes from the existing USP–NF monograph include:

  • Definition
    • Changed from “a partially substituted poly(hydroxypropyl) ether of cellulose” to “partly O-(2-hydroxypropylated) cellulose”.
    • Changed from “When dried at 1050 for 1h, it contains NMT 80.5% of hydroxypropoxy groups.” to “It contains NLT 53.4% and NMT 80.5% of hydroxypropoxy groups, calculated on the dried basis.” to reflect the addition of a new GC capillary assay test for Hydroxypropoxy Groups
    • Changed from “It may contain NMT 0.60% of silica or other suitable anticaking agents.” to “It may contain suitable anti-caking agents, such as silica.”
  • Identification
    • Changed the Note for Infrared test from “The spectrum may or may not contain a peak at about 1719 cm-1.” to “Disregard any peak at about 1719 cm-1.”
    • Added an orthogonal identification to test thin film formation.
  • Assay
    • Replaced the previous titrimetric method for assay of hydroxypropoxy groups by a new GC capillary method.
  • Residue on Ignition and Silica test,
    • Changed the verbiage of procedure and acceptance criteria to align with PDG Stage 6 sign-off document.
  • pH
    • Added “prepared by evenly distributing the powder into boiling carbon dioxide free water and stirring the mixture with a magnetic stirrer.”
  • Loss on Drying
    • Changed from “3h” to “4h”.
  • Labeling
    • Added “Suitable anti-caking agents, such as silica, should be stated on the label”.

In addition, the monograph has been edited to be consistent with the current USP style guide.

The Hydroxypropyl Cellulose monograph will be incorporated into and become official with the Second Supplement to USP 37–NF 32.

*Should you have any questions about the Hydroxypropyl 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 Group or contact Richard Lew at (240-221-2060 or rll@usp.org).

*The previous sign-offs and Stage 6 postings are included as below: