Standard Operating Procedure for In-Process Viscosity Testing of Gel Formulations
| Department | Gel Manufacturing |
|---|---|
| SOP No. | SOP/GM/074/2025 |
| Supersedes | SOP/GM/074/2022 |
| Page No. | Page 1 of 10 |
| Issue Date | 02/06/2025 |
| Effective Date | 04/06/2025 |
| Review Date | 02/06/2026 |
1. Purpose
To define a standardized procedure for conducting in-process viscosity testing of gel formulations during manufacturing, ensuring consistency and compliance with product specifications.
2. Scope
This procedure applies to all gel formulations manufactured in the Gel Manufacturing Department requiring viscosity control during intermediate stages before final approval for packaging.
3. Responsibilities
- Production Chemist: Responsible for
sampling, operating viscometer, and recording results.
Quality Control Analyst: Responsible for cross-verification and releasing results.
Quality Assurance: Responsible for auditing the records and ensuring GMP compliance.
4. Accountability
Head – Manufacturing is accountable for compliance with this SOP and implementation of corrective action where necessary.
5. Procedure
5.1 Pre-Test Preparation
- Ensure that the viscometer is cleaned and calibrated as per SOP.
- Wear appropriate PPE including gloves, goggles, and apron.
- Label the clean sample containers with Batch No., Date, and Time.
5.2 Sampling Procedure
- Draw the sample from the manufacturing vessel using sanitized stainless-steel scoop/spatula.
- Collect about 100 g of gel in the labeled container.
- Ensure minimum air entrapment during sampling to avoid erroneous viscosity readings.
5.3 Instrument Setup
- Switch ON the viscometer and allow it to stabilize for 10 minutes.
- Select appropriate spindle and speed setting based on the viscosity range of the gel (e.g., spindle #6 at 10 rpm for 20,000–60,000 cps).
- Immerse the spindle into the gel ensuring no bubbles cling to the surface.
5.4 Viscosity Measurement
- Start the instrument and allow 1–2 minutes for reading stabilization.
- Record the viscosity reading in centipoise (cP or cps) once the reading stabilizes.
- Repeat the measurement thrice and record average value in the In-Process Viscosity Log (Annexure-1).
5.5 Criteria for Acceptance
- Compare average value against the batch specification (defined in BMR).
- If the viscosity is out of range:
- Stop further processing.
- Inform Production and QA for decision on corrective measures such as further homogenization or dilution.
5.6 Post-Test Clean-Up
- Clean spindle and beakers with purified water and suitable solvent if required.
- Document cleaning as per instrument cleaning SOP.
- Ensure calibration sticker is intact and valid.
6. Abbreviations
- PPE: Personal Protective Equipment
- BMR: Batch Manufacturing Record
- QA: Quality Assurance
- QC: Quality Control
7. Documents
- In-Process Viscosity Log – Annexure-1
- Viscometer Calibration Log – Annexure-2
8. References
- USP <911> – Viscosity
- ICH Q8 (R2) – Pharmaceutical Development
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: In-Process Viscosity Log
| Date | Batch No. | Spindle No. | Speed (rpm) | Reading 1 (cps) | Reading 2 (cps) | Reading 3 (cps) | Average (cps) | Checked By |
|---|---|---|---|---|---|---|---|---|
Annexure-2: Viscometer Calibration Log
| Instrument ID: | |
| Calibration Date: | |
| Calibrated By: | |
| Standard Used: | Brookfield Certified Oil (20,000 cps) |
| Observed Reading: | |
| Status: | Pass/Fail |
| Next Calibration Due: |
Revision History
| Revision Date | Revision No. | Change Description | Reason | Approved By |
|---|---|---|---|---|
| 05/06/2022 | 1.0 | Initial issue | Procedure release | QA Head |
| 02/06/2025 | 2.0 | Revised with annexure templates and control steps | Compliance Improvement | QA Head |