Procedure for Adding Viscosity Modifiers in the Mixing Process

Department	Manufacturing/Production/Quality Assurance (QA)/Quality Control (QC)/Research and Development (R&D)
SOP No.	SOP/Ointment/193
Supersedes	V 1.0
Page No.	Page X of Y
Issue Date	[Insert Issue Date]
Effective Date	[Insert Effective Date]
Review Date	[Insert Review Date]

1. Purpose

The purpose of this Standard Operating Procedure (SOP) is to define a systematic approach for adding viscosity modifiers in the mixing process of pharmaceutical ointments. Proper incorporation of viscosity modifiers ensures batch uniformity, stability, and optimal spreadability of the final product.

2. Scope

This SOP applies to all personnel involved in the preparation, addition, and quality control of viscosity modifiers in the Manufacturing, Production, Quality Assurance (QA), Quality Control (QC), and Research and Development (R&D) departments.

3. Responsibilities

• Production Supervisor: Ensures adherence to viscosity modifier addition protocol.
• Process Operator: Monitors and controls mixing conditions for proper dispersion.
• QA Officer: Verifies the consistency of the batch after viscosity modification.
• QC Analyst: Conducts viscosity and homogeneity tests.
• Maintenance Engineer: Ensures mixing equipment operates within defined parameters.

4. Accountability

The Production Manager is accountable for ensuring that all viscosity modifier addition procedures comply with GMP, FDA, ICH, WHO, and company policies.

5. Procedure

5.1 Selection of Viscosity Modifiers

• Common viscosity modifiers used in ointment manufacturing include:
  • Carbomers
  • Hydroxyethyl cellulose (HEC)
  • Xanthan gum
  • Polyacrylic acid derivatives
  • Silica-based thickeners
• Ensure that the selected viscosity modifier is compatible with the formulation.
• Document selection in the **Viscosity Modifier Selection Log (Annexure-1).**

5.2 Preparation Before Addition

• Ensure that all required ingredients and excipients are available and within specifications.
• Verify the calibration of weighing balances and mixing equipment.
• Adjust the mixing speed based on the viscosity modifier type.
• Record pre-addition checks in the **Pre-Addition Checklist (Annexure-2).**

5.3 Addition Process

• Gradually introduce the viscosity modifier into the mixing tank.
• Maintain an optimal **mixing speed between 100-300 RPM** to avoid clumping.
• If required, pre-disperse the viscosity modifier in a suitable solvent before addition.
• Ensure even dispersion by **mixing continuously for 15-30 minutes.**
• Document addition parameters in the **Viscosity Modifier Addition Log (Annexure-3).**

5.4 Quality Control Testing

• Measure viscosity using a **Brookfield Viscometer or equivalent.**
• Conduct **homogeneity tests** to confirm even distribution of the modifier.
• Compare viscosity values against predetermined specifications.
• Document all test results in the **Viscosity Testing Log (Annexure-4).**

6. Abbreviations

• GMP – Good Manufacturing Practices
• QA – Quality Assurance
• QC – Quality Control
• ICH – International Council for Harmonisation
• FDA – Food and Drug Administration

7. Documents

• Viscosity Modifier Selection Log (Annexure-1)
• Pre-Addition Checklist (Annexure-2)
• Viscosity Modifier Addition Log (Annexure-3)
• Viscosity Testing Log (Annexure-4)

8. References

• ICH Q8 – Pharmaceutical Development Guidelines
• FDA Guidance on Topical Formulation Processing
• WHO Guidelines on Manufacturing Quality Control

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 Modifier Selection Log

Date	Batch No.	Modifier Used	Quantity (g)	QA Approval

Annexure-2: Pre-Addition Checklist

Date	Batch No.	Equipment Checked	Materials Verified	QA Approval

Annexure-3: Viscosity Modifier Addition Log

Date	Batch No.	Modifier Added	Mixing Speed (RPM)	QA Approval

Annexure-4: Viscosity Testing Log

Date	Batch No.	Viscosity (cP)	Test Equipment	QA Approval

12. Revision History

Revision Date	Revision No.	Details	Reason	Approved By
02/02/2025	2.0	Expanded Viscosity Modifier Addition Guidelines	Regulatory Compliance	QA Head