Procedure for Water Content Analysis in Ointments
| Department | Quality Control (QC)/Quality Assurance (QA)/Analytical Development |
|---|---|
| SOP No. | SOP/Ointment/067 |
| 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 the method for determining the water content in ointments. Water content is a critical parameter that affects product stability, texture, microbial growth, and compliance with product specifications.
2. Scope
This SOP applies to all personnel in the Quality Control (QC), Quality Assurance (QA), and Analytical Development departments responsible for conducting water content analysis in ointments during formulation development, in-process control, and final batch release.
3. Responsibilities
- Quality Control Analyst: Conducts water content analysis and records results.
- Quality Assurance Personnel: Reviews and approves test results.
- Production Supervisor: Ensures that ointment batches conform to water content specifications.
- R&D and Analytical Development Team: Evaluates formulation modifications based on water content test results.
4. Accountability
The QC, Analytical Development, and QA Managers are accountable for ensuring that water content analysis is conducted accurately and documented as per regulatory and GMP standards.
5. Procedure
5.1 Equipment and Materials
- Karl Fischer Titrator
- Oven (for Loss on Drying Method, if applicable)
- Weighing balance (calibrated)
- Titrant solution (Karl Fischer reagent)
- Solvent (e.g., methanol, formamide)
- Disposable pipettes
- Glassware (volumetric flasks,
beakers)
Data recording sheets
5.2 Sample Preparation
- Weigh an appropriate quantity of the ointment sample (e.g., 0.5 g – 1 g).
- Transfer into a suitable solvent to dissolve the sample.
- Ensure complete homogenization before analysis.
5.3 Water Content Determination Methods
5.3.1 Karl Fischer Titration Method
- Ensure the Karl Fischer Titrator is calibrated and filled with reagent.
- Prepare the sample solution in an appropriate solvent.
- Inject the sample into the Karl Fischer Titrator.
- Allow titration until the endpoint is reached.
- Record the water content percentage displayed by the instrument.
5.3.2 Loss on Drying (LOD) Method (If Applicable)
- Weigh the sample in a pre-weighed moisture dish.
- Place the dish in an oven at 105°C for 2 hours.
- Remove and allow to cool in a desiccator.
- Weigh again and calculate the water content using:
- Water Content (%) = [(Initial Weight – Final Weight) / Initial Weight] × 100
5.4 Acceptance Criteria
- Water content should be within the specified range (e.g., 1% – 5% depending on the formulation).
- Deviations from specifications require investigation and possible batch reprocessing.
5.5 Documentation
- Record all water content analysis results in the Water Content Test Log.
- Document instrument calibration details and method parameters.
- QA personnel must review and approve results before batch release.
6. Abbreviations
- GMP – Good Manufacturing Practices
- QA – Quality Assurance
- QC – Quality Control
- LOD – Loss on Drying
- KF – Karl Fischer Titration
7. Documents
- Water Content Test Log (Annexure-1)
- Ointment Batch Water Content Report (Annexure-2)
8. References
- WHO GMP Guidelines for Pharmaceutical Manufacturing
- USP <921> – Water Determination
- ICH Q2 (R1) – Validation of Analytical Procedures
9. SOP Version
Version 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Water Content Test Log
| Date | Batch Number | Sample Weight (g) | Water Content (%) | Result | Verified By |
|---|---|---|---|---|---|
| 01/02/2025 | OINT-101 | 0.5 | 2.5% | Pass | QA Officer |
| 02/02/2025 | OINT-102 | 0.5 | 3.1% | Pass | QA Officer |
Annexure-2: Ointment Batch Water Content Report
| Date | Batch Number | Test Method | Acceptance Criteria | Result | Final Status | Approved By |
|---|---|---|---|---|---|---|
| 01/02/2025 | OINT-101 | Karl Fischer | 1% – 5% | 2.5% | Approved | QA Head |
| 02/02/2025 | OINT-102 | Loss on Drying | 1% – 5% | 3.1% | Approved | QA Head |
12. Revision History:
| Revision Date | Revision No. | Details of Revision | Reason for Revision | Approved By |
|---|---|---|---|---|
| 01/01/2024 | 1.0 | Initial Version | New SOP | QA Head |
| 01/02/2025 | 2.0 | Updated SOP Format | Standardization of Document | QA Head |