Elixir Department: SOP for Viscosity Measurement Using Brookfield Viscometer – V 2.0

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Elixir Department: SOP for Viscosity Measurement Using Brookfield Viscometer – V 2.0

Standard Operating Procedure for Viscosity Measurement of Elixir Using Brookfield Viscometer

Department Elixir Department
SOP No. SOP/ELX/215/2025
Supersedes SOP/ELX/215/2022
Page No. Page 1 of 9
Issue Date 11/04/2025
Effective Date 15/04/2025
Review Date 11/04/2026

1. Purpose

To establish a standardized method for determining the viscosity of elixir formulations using a Brookfield Viscometer. This ensures the product meets defined consistency, flowability, and stability parameters.

2. Scope

This SOP is applicable to all final elixir batches requiring viscosity testing during in-process or finished product quality control checks in the QC Laboratory.

3. Responsibilities

  • QC Analyst:
    • Prepare and test the sample, operate the Brookfield Viscometer, and record results.
  • QC Supervisor:
    • Verify the results, ensure equipment calibration, and review data.
  • QA Officer:
    • Audit records and ensure compliance with GMP documentation practices.

4. Accountability

The QC Head is accountable for the accurate execution and reporting of viscosity test results. The QA Head ensures GMP compliance and regulatory readiness.

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5. Procedure

5.1 Instrument Setup

  1. Ensure the Brookfield Viscometer is placed on a vibration-free,
level surface.
  • Connect the viscometer to a power source and switch it on.
  • Verify calibration status and select appropriate spindle as per method (e.g., Spindle #2 for low viscosity).

    • 5.2 Sample Preparation

    1. Transfer approximately 100 mL of the elixir sample into a clean, dry 150 mL beaker or container.
    2. Ensure sample temperature is maintained at 25 ± 2°C. Use a calibrated thermometer to verify.
    3. Stir gently to ensure uniformity without introducing air bubbles.

    5.3 Test Execution

    1. Lower the selected spindle into the center of the sample without touching the bottom or sides.
    2. Select the appropriate speed (typically 30 rpm, unless specified otherwise).
    3. Allow the reading to stabilize for at least 30 seconds before recording the viscosity.
    4. Record the reading in centipoise (cP) or mPa.s as displayed on the screen.

    5.4 Repeatability and Validation

    1. Repeat the test at least three times with fresh aliquots of the same sample to ensure consistency.
    2. Calculate the average viscosity and standard deviation.
    3. Acceptable relative standard deviation (RSD) must not exceed 2%.

    5.5 Post-Test Cleaning

    1. Remove the spindle and rinse with purified water, followed by cleaning with a mild detergent if necessary.
    2. Dry the spindle with lint-free tissue and store in a designated spindle stand.

    5.6 Acceptance Criteria

    1. The viscosity must be within the limits specified in the approved specification (e.g., 50 – 150 cP, depending on formulation).
    2. Any deviation must be reported to QA and investigated as per deviation SOP.

    5.7 Documentation

    1. Record all test details in the Viscosity Test Logbook (Annexure-1).
    2. Include batch number, date, instrument ID, spindle type, speed, temperature, and results.
    3. Attach printed reports (if applicable) to the BMR.

    6. Abbreviations

    • SOP: Standard Operating Procedure
    • QC: Quality Control
    • QA: Quality Assurance
    • BMR: Batch Manufacturing Record
    • RPM: Revolutions per Minute
    • RSD: Relative Standard Deviation

    7. Documents

    1. Viscosity Test Logbook (Annexure-1)
    2. Instrument Calibration Logbook
    3. Batch Manufacturing Record (BMR)

    8. References

    • USP General Chapter <911> – Viscosity
    • 21 CFR Part 211.160 – Laboratory Controls
    • ICH Q6A – Specifications: Test Procedures and Acceptance Criteria

    9. SOP Version

    Version: 2.0

    10. Approval Section

    Prepared By Checked By Approved By
    Signature
    Date
    Name
    Designation
    Department

    11. Annexures

    Annexure-1: Viscosity Test Logbook

    Date Batch No. Spindle RPM Temperature (°C) Viscosity (cP) RSD (%) Tested By Verified By
    11/04/2025 ELX-0425-033 #2 30 25.1 97.8 1.2 Rajesh Kumar Sunita Reddy

    Revision History:

    Revision Date Revision No. Revision Details Reason for Revision Approved By
    01/01/2024 1.0 Initial Release New SOP QA Head
    11/04/2025 2.0 Included repeatability and spindle guidance Method Enhancement QA Head
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