Accelerated Stability Testing of Emulsion Formulations
1) Purpose
The purpose of this SOP is to describe the procedure for conducting accelerated stability testing on emulsion formulations. This testing simulates long-term storage conditions by exposing the emulsion to elevated temperatures and humidity levels over a short period. It helps predict the shelf life of the formulation by observing changes in physical and chemical stability under stress conditions.
2) Scope
This SOP applies to personnel involved in the stability testing of emulsion formulations in pharmaceutical development. It covers the preparation, storage, and evaluation of emulsion samples under accelerated conditions to assess their stability and predict long-term behavior.
3) Responsibilities
- Formulation Scientists: Responsible for preparing emulsion batches for accelerated stability testing and ensuring sample uniformity.
- QC Team: Responsible for conducting physical and chemical stability tests at specified intervals and documenting the results.
- QA Team: Responsible for reviewing stability study results and ensuring compliance with regulatory standards.
4) Procedure
4.1 Preparation for Accelerated Testing
- 4.1.1 Prepare emulsion formulations as per the manufacturing protocol. Ensure that the samples are uniform and representative of the batch.
- 4.1.2 Label the samples with batch number, preparation date, and storage conditions.
- 4.1.3 Divide the samples into groups for different storage conditions, such as 40°C/75% RH (relative humidity) for accelerated testing and 25°C/60% RH for comparative testing.
4.2 Parameters for Stability Testing
The following parameters should be monitored during the stability study to assess physical and chemical stability:
- 4.2.1 Droplet Size Distribution: Measure droplet size using dynamic light scattering (DLS) or laser diffraction at each time point. Monitor for significant changes that may indicate coalescence or instability.
- 4.2.2 Zeta Potential: Measure zeta potential to assess the colloidal stability of the emulsion.
- 4.2.3 Phase Separation: Visually inspect the emulsion for signs of phase separation, creaming, or sedimentation.
- 4.2.4 Viscosity: Measure viscosity at each time point to assess consistency and flow properties.
- 4.2.5 pH: Measure the pH of the emulsion at each interval. Significant pH changes may affect stability or performance.
4.3 Sampling and Testing Time Points
- 4.3.1 Initial Test: Conduct the initial tests immediately after preparing the emulsion to establish baseline stability parameters.
- 4.3.2 Interim Tests: Perform stability tests at specified intervals (e.g., 1 month, 3 months, 6 months) for samples stored at 40°C/75% RH.
- 4.3.3 Final Test: Conduct the final stability tests at the end of the study period (e.g., 6 months) to determine overall stability under accelerated conditions.
4.4 Data Recording and Analysis
- 4.4.1 Record all test results in the Stability Test Report (see Annexure 1 for the template).
- 4.4.2 Compare results with baseline values to identify trends such as droplet size increase, zeta potential reduction, or phase separation.
- 4.4.3 Analyze the data to estimate the shelf life of the emulsion formulation under accelerated conditions.
4.5 Criteria for Stability
The emulsion formulation is considered stable under accelerated conditions if it meets the following criteria throughout the study:
- 4.5.1 Droplet size distribution remains within acceptable limits, with no significant increase or coalescence.
- 4.5.2 Zeta potential remains within the range that indicates good colloidal stability (typically ±30 mV or higher).
- 4.5.3 No visible signs of phase separation, creaming, or sedimentation.
- 4.5.4 Viscosity remains within acceptable limits, with no significant changes.
5) Abbreviations, if any
- DLS: Dynamic Light Scattering
- RH: Relative Humidity
- QC: Quality Control
- QA: Quality Assurance
6) Documents, if any
- Batch Manufacturing Record (BMR)
- Stability Test Report
- Droplet Size Analysis Report
- Zeta Potential Measurement Report
- Viscosity Measurement Report
7) References, if any
- ICH Q1A: Stability Testing of New Drug Substances and Products
- FDA Guidelines for Stability Testing of Emulsion Products
8) SOP Version
Version 1.0
Annexure
Annexure 1: Stability Test Report Template
| Time Point | Storage Condition | Droplet Size (nm) | Zeta Potential (mV) | Viscosity (cP) | Phase Separation | pH | Operator Initials |
|---|---|---|---|---|---|---|---|
| Initial | 40°C/75% RH | 100-200 nm | -30 to -50 mV | 10 cP | No | 7.0 | Operator Name |
| 1 Month | 40°C/75% RH | 100-200 nm | -30 to -50 mV | 10 cP | No | 7.0 | Operator Name |
| 3 Months | 40°C/75% RH | 100-200 nm | -30 to -50 mV | 10 cP | No | 7.0 | Operator Name |