Microbiological Stability Testing of Emulsions
1) Purpose
The purpose of this SOP is to describe the procedure for conducting microbiological stability testing on emulsion formulations. This ensures that the emulsions remain free from microbial contamination during storage, maintaining product quality and safety over their shelf life.
2) Scope
This SOP applies to all personnel involved in microbiological stability testing, including the QC microbiology team. It covers the evaluation of microbial contamination over time for both sterile and non-sterile emulsions.
3) Responsibilities
- QC Microbiology Team: Responsible for conducting microbiological tests and documenting the results at defined intervals.
- QA Team: Responsible for reviewing and approving test results and ensuring compliance with regulatory guidelines.
- Formulation Scientists: Responsible for preparing sterile and non-sterile emulsion samples for microbiological testing.
4) Procedure
4.1 Sample Preparation
- 4.1.1 Prepare emulsion formulations in sterilized containers (for sterile emulsions) or controlled aseptic conditions (for non-sterile emulsions).
- 4.1.2 Label the samples with the batch number, preparation date, and storage conditions.
- 4.1.3 Store samples under appropriate conditions for stability testing (e.g., 25°C/60% RH, 40°C/75% RH).
4.2 Microbiological Testing Parameters
The following microbiological tests should be performed at specified intervals:
- 4.2.1 Total Aerobic Microbial Count (TAMC): Perform microbial enumeration to determine the number of viable aerobic microorganisms in the emulsion.
- 4.2.2 Total Yeast and
Mold Count (TYMC): Perform microbial enumeration to determine the number of viable yeast and mold colonies.
4.2.3 Pathogen Detection: Test for the presence of specific pathogens (e.g., Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli) using selective media.
4.3 Testing Schedule
- 4.3.1 Initial Test: Conduct microbiological tests immediately after sample preparation to establish a baseline for contamination levels.
- 4.3.2 Interim Tests: Perform microbiological testing at specified intervals (e.g., 1 month, 3 months, 6 months) during storage.
- 4.3.3 Final Test: Conduct a final microbiological test at the end of the stability study (e.g., 12 months) to confirm the microbiological stability of the emulsion.
4.4 Data Recording and Analysis
- 4.4.1 Record all test results in the Microbiological Stability Test Report (see Annexure 1).
- 4.4.2 Compare the results with regulatory limits to ensure that microbial levels remain within acceptable ranges.
- 4.4.3 Analyze trends in microbial growth to determine the risk of contamination and the effectiveness of preservatives used in the formulation.
4.5 Acceptance Criteria
The emulsion formulation is considered microbiologically stable if the following criteria are met throughout the study:
- 4.5.1 The total aerobic microbial count (TAMC) remains within acceptable limits as defined by regulatory guidelines.
- 4.5.2 The total yeast and mold count (TYMC) remains within acceptable limits.
- 4.5.3 No specific pathogens are detected throughout the study period.
5) Abbreviations
- TAMC: Total Aerobic Microbial Count
- TYMC: Total Yeast and Mold Count
- QC: Quality Control
- QA: Quality Assurance
6) Documents
- Microbiological Stability Test Report
- Batch Manufacturing Record (BMR)
- Microbial Enumeration Test Report
- Pathogen Detection Report
7) References
- USP <61>: Microbiological Examination of Non-Sterile Products
- ICH Q6A: Specifications for New Drug Substances and Products
8) SOP Version
Version 1.0
Annexure
Annexure 1: Microbiological Stability Test Report Template
| Time Point | Storage Condition | TAMC (cfu/mL) | TYMC (cfu/mL) | Pathogens | Operator Initials |
|---|---|---|---|---|---|
| Initial | 25°C/60% RH | Below Limit | Below Limit | None | Operator Name |
| 1 Month | 40°C/75% RH | Below Limit | Below Limit | None | Operator Name |
| 3 Months | 40°C/75% RH | Below Limit | Below Limit | None | Operator Name |