Control Analyst: To perform viscosity testing as per the approved test method.

QC Supervisor: To review test data and ensure compliance with specifications.

QA Officer: To verify compliance and support investigations for OOS or deviation.

4. Accountability

The Head – Quality Control shall be accountable for ensuring adherence to this SOP.

5. Procedure

5.1 Instrumentation

• Brookfield Viscometer with appropriate spindle (or equivalent rheometer).
• Calibrated stopwatch.
• Water bath (if testing requires temperature control).

5.2 Sample Preparation

1. Collect a representative sample of the gel as per the sampling SOP.
2. Ensure the sample is free of bubbles and homogenized before testing.
3. If necessary, allow the sample to equilibrate to the specified testing temperature (typically 25°C).

5.3 Instrument Calibration

1. Calibrate the viscometer using standard viscosity reference oils before use.
2. Record calibration details in the instrument calibration log.

5.4 Viscosity Measurement

1. Assemble the viscometer and select the correct spindle based on the expected viscosity range.
2. Immerse the spindle into the sample ensuring it is centered and not touching the container walls.
3. Set the appropriate RPM as per the validated test method.
4. Start the viscometer and record the viscosity once the reading stabilizes.
5. Repeat measurements in triplicate and record the average value.

5.5 Acceptance Criteria

• The viscosity result should comply with the limits specified in the product specification sheet.

5.6 Handling OOS Results

1. Immediately notify QC Supervisor and QA if results are outside specification.
2. Follow the OOS investigation SOP.

5.7 Documentation

1. Record results in the Viscosity Logbook and Analytical Report.
2. Attach instrument printouts, if available, to the report.
3. Submit documentation for verification and approval.

6. Abbreviations

• QC: Quality Control
• QA: Quality Assurance
• OOS: Out of Specification
• SOP: Standard Operating Procedure

7. Documents

1. Viscosity Test Logbook – Annexure-1
2. Analytical Test Report – Annexure-2
3. Viscometer Calibration Log – Annexure-3

8. References

• USP General Chapter <912> – Viscosity
• ICH Q6A – Specifications
• Internal product specification document

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation	Jr. Production Chemist	QA Executive	Head – Manufacturing
Department	Gel Manufacturing	Quality Assurance	Manufacturing

11. Annexures

Annexure-1: Viscosity Test Logbook Format

Date	Batch No.	Product Name	Spindle/RPM	Viscosity (cP)	Analyst	Remarks

Annexure-2: Analytical Test Report Template

Test	Method	Specification	Result	Conclusion
Viscosity	Internal Method No. XYZ	35000–45000 cP

Annexure-3: Viscometer Calibration Log

Date	Instrument ID	Standard Oil Used	Expected cP	Measured cP	Performed By	Reviewed By

Revision History

Revision Date	Revision No.	Details	Reason	Approved By
15/04/2022	1.0	Initial version issued	New SOP	QA Head
02/06/2025	2.0	Revised for equipment update and format standardization	Audit compliance	QA Head