SOP Guide for Pharma

Elixir Department: SOP for Viscosity Testing During Mixing – V 2.0

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Elixir Department: SOP for Viscosity Testing During Mixing – V 2.0

Standard Operating Procedure for Viscosity Testing During Mixing in Elixir Manufacturing

Department Elixir Department
SOP No. SOP/ELX/193/2025
Supersedes SOP/ELX/193/2022
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 consistent procedure for monitoring and recording viscosity during the mixing process in elixir manufacturing to ensure batch-to-batch consistency and product quality.

2. Scope

This SOP applies to all elixir formulations where viscosity is a critical quality attribute (CQA) and must be monitored in real-time or at predefined mixing intervals within the Elixir Manufacturing Department.

3. Responsibilities

  • Production Operator:
    • Conduct viscosity testing using the designated viscometer at defined stages of mixing.
    • Document viscosity values in the logbook.
  • QC Analyst:
    • Verify and re-test critical viscosity readings when required.
  • QA Officer:
    • Ensure that viscosity measurements are performed and recorded in compliance with SOP.
See also  Elixir Department: SOP for Time-Based Sampling Schedule - V 2.0

4. Accountability

The Production Head is accountable for ensuring that viscosity testing is performed at specified intervals. The QA Head ensures GMP compliance and documentation review.

5. Procedure

5.1

Equipment and Preparation
  1. Use a calibrated rotational viscometer (e.g., Brookfield Viscometer) suitable for liquid formulations.
  2. Ensure spindle selection is appropriate for expected viscosity range.
  3. Verify calibration using standard viscosity reference fluid before use.
  4. Record calibration in the Equipment Calibration Logbook.

5.2 Sampling for Viscosity

  1. Collect 100 mL of elixir from the mixing tank using a clean sampling beaker.
  2. Ensure the sample is free from air bubbles and taken after homogenized mixing.
  3. Record the temperature of the sample before testing.

5.3 Viscosity Measurement

  1. Immerse the spindle fully in the sample as per instrument guidelines.
  2. Select the correct RPM and spindle based on the validation protocol.
  3. Allow reading to stabilize for 30–60 seconds before recording the value in centipoise (cP).
  4. Measure viscosity at predefined time points:
    • After 50% mixing time
    • At end of mixing
    • Just before cooling or filtration

5.4 Acceptance Criteria and Actions

  1. Compare recorded values with the product specification range defined in the BMR.
  2. If out-of-specification (OOS), notify QA and hold the batch.
  3. Investigate possible causes (e.g., incomplete dissolution, incorrect ingredient quantity).

5.5 Cleaning and Maintenance

  1. Clean spindle with purified water or appropriate solvent immediately after use.
  2. Dry and store as per equipment SOP.

5.6 Documentation

  1. Record viscosity results in the Viscosity Monitoring Logbook (Annexure-1).
  2. Include Batch No., Sample Time, Temperature, Spindle No., RPM, and Observed Viscosity.
  3. QA shall verify log entries and sign off.

6. Abbreviations

  • SOP: Standard Operating Procedure
  • QA: Quality Assurance
  • QC: Quality Control
  • RPM: Revolutions Per Minute
  • cP: Centipoise

7. Documents

  1. Viscosity Monitoring Logbook (Annexure-1)
  2. BMR Reference Sheet
  3. Viscometer Calibration Log

8. References

  • ICH Q8 – Pharmaceutical Development
  • 21 CFR Part 211.110 – Sampling and Testing of In-Process Materials
  • WHO TRS 986 – GMP Guidelines

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 Monitoring Logbook

Date Batch No. Time Point Spindle/RPM Observed Viscosity (cP) Temperature (°C) Operator QA Verified
11/04/2025 ELX-0425-012 Post-Mixing S62 / 60 120 cP 27.5 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 Added specific sampling stages and QC retest clause Process Improvement QA Head
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