Standard Operating Procedure for Preliminary Stability Testing of Gel Formulations
| Department | Gel Manufacturing |
|---|---|
| SOP No. | SOP/GM/014/2025 |
| Supersedes | SOP/GM/014/2022 |
| Page No. | Page 1 of 12 |
| Issue Date | 02/06/2025 |
| Effective Date | 04/06/2025 |
| Review Date | 02/06/2026 |
1. Purpose
This SOP outlines the procedure for conducting preliminary stability studies on gel formulations to determine their physical, chemical, and microbiological integrity under different storage conditions prior to formal stability trials.
2. Scope
This procedure applies to all new or modified gel formulations developed in the
Gel Manufacturing R&D department of the pharmaceutical unit.
3. Responsibilities
- Formulation Scientist: Responsible for preparing samples and coordinating with the analytical team.
- Quality Control Analyst: Responsible for testing physical, chemical, and microbiological parameters at defined intervals.
- R&D Supervisor: Responsible for reviewing data and making decisions on further formulation development.
4. Accountability
The Head – R&D shall be accountable for the implementation and compliance with this SOP.
5. Procedure
5.1 Sample Preparation
- Prepare three representative gel batches (lab scale) using standard manufacturing procedures.
- Fill approximately 20g of each gel formulation into clean, labeled laminated tubes or HDPE containers.
- Ensure sample identification includes formulation code, batch number, date of manufacture, and analyst initials.
5.2 Storage Conditions
- Store the filled containers at the following stability conditions:
- Refrigerated: 5°C ± 3°C
- Ambient: 25°C ± 2°C / 60% RH ± 5%
- Accelerated: 40°C ± 2°C / 75% RH ± 5%
5.3 Time Points for Evaluation
- Day 0 (Initial)
- 1 Week
- 2 Weeks
- 4 Weeks
5.4 Parameters for Testing
- Physical Appearance: Color, clarity, phase separation, and grittiness.
- pH: Measured using a calibrated pH meter.
- Viscosity: Determined using a Brookfield viscometer (RV or LV as applicable).
- Assay: API content via validated HPLC or UV method.
- Microbial Load: Total aerobic microbial count and fungal count.
5.5 Documentation and Analysis
- Record results in Preliminary Stability Study Data Sheet (Annexure-1).
- Summarize findings in Preliminary Stability Study Summary Report (Annexure-2).
- Determine trends, degradation, or unacceptable changes that may influence final formulation design.
5.6 Acceptance Criteria
- No significant phase separation, discoloration, or odor development.
- pH variation within ±0.5 units from initial value.
- Assay within 95% to 105% of labeled claim.
- Total aerobic microbial count < 100 CFU/g; yeast and molds < 10 CFU/g.
6. Abbreviations
- SOP: Standard Operating Procedure
- API: Active Pharmaceutical Ingredient
- CFU: Colony Forming Units
- RH: Relative Humidity
7. Documents
- Preliminary Stability Study Data Sheet – Annexure-1
- Preliminary Stability Summary Report – Annexure-2
- Microbial Testing Data Sheet – Annexure-3
8. References
- ICH Q1A(R2): Stability Testing of New Drug Substances and Products
- USP General Chapter <51> Antimicrobial Effectiveness Testing
- Internal formulation development reports
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: Preliminary Stability Study Data Sheet
| Date | Condition | pH | Viscosity | Appearance | Assay (%) |
|---|---|---|---|---|---|
| Day 0 | Ambient | 6.5 | 18000 | Clear gel | 99.6 |
Annexure-2: Preliminary Stability Summary Report
| Formulation Code | Storage Condition | Observations | Conclusion |
|---|---|---|---|
| GF-001 | 40°C/75% RH | Color change at 4 weeks | Requires preservative modification |
Annexure-3: Microbial Testing Data Sheet
| Sample ID | TAMC (CFU/g) | TYMC (CFU/g) | Complies |
|---|---|---|---|
| GEL-STB-001 | 10 | 2 | Yes |
Revision History:
| Revision Date | Revision No. | Details | Reason | Approved By |
|---|---|---|---|---|
| 01/06/2022 | 1.0 | Initial version | New SOP | Head – R&D |
| 02/06/2025 | 2.0 | Added microbial testing and acceptance criteria | Stability study expansion | Head – R&D |