Standard Operating Procedure for Preservative Efficacy Testing in Creams
1) Purpose
The purpose of this SOP is to outline the procedures for testing the efficacy of preservatives in creams to ensure the product’s microbiological stability and safety over its shelf-life.
2) Scope
This SOP applies to all personnel involved in the microbiological testing of creams, including laboratory technicians, microbiologists, and quality assurance (QA) personnel. It covers procedures for sample preparation, preservative efficacy testing, and documentation.
3) Responsibilities
It is the responsibility of laboratory technicians to prepare and test samples, microbiologists to validate the preservative efficacy testing method, and QA personnel to review and approve the test results.
4) Procedure
4.1 Preparation for Preservative Efficacy Testing
4.1.1 Review the batch record and sampling plan to determine the number of samples to be analyzed.
4.1.2 Ensure all testing equipment (e.g., incubators, laminar flow hoods) is calibrated and in proper working condition.
4.1.3 Prepare all necessary media, reagents, and inoculum suspensions according to the validated method.
4.1.4 Label all sample containers with necessary information, including sample ID, batch number, and date of preparation.
4.1.5 Wear appropriate personal protective equipment (PPE) such as gloves, lab coat, and safety glasses to avoid contamination.
4.2 Sample Preparation
4.2.1 Weigh an appropriate amount of cream sample into a sterile container, as specified in the validated preservative efficacy testing method.
4.2.2 Prepare inoculum suspensions of the specified microorganisms (e.g., bacteria, yeast, mold) at the required concentration.
4.2.3 Inoculate the cream sample with the microorganism suspension, ensuring homogeneous distribution.
4.3 Preservative Efficacy Testing
4.3.1 Incubate Method:
4.3.1.1 Place the inoculated cream sample in sterile containers and incubate at specified temperatures (e.g., 25°C, 37°C) for a defined period (e.g., 7 days, 14 days, 28 days).
4.3.1.2 At specified intervals (e.g., 7, 14, 28 days), withdraw aliquots of the inoculated cream sample using aseptic techniques.
4.3.1.3 Plate the aliquots onto appropriate agar media to enumerate surviving microorganisms.
4.3.1.4 Incubate the agar plates at specified conditions (e.g., 30°C for 48 hours) and count the colony-forming units (CFUs).
4.3.1.5 Calculate the log reduction in microbial count to determine the preservative efficacy.
4.4 Quality Control
4.4.1 Perform the preservative efficacy test in duplicate or triplicate to ensure accuracy and precision.
4.4.2 Include quality control (QC) samples and reference standards in the analysis run to verify the reliability of the results.
4.4.3 Compare the preservative efficacy test results with the specification limits to determine if the batch meets the required criteria.
4.5 Documentation and Review
4.5.1 Document all details of the preservative efficacy testing procedure, including sample preparation, inoculation, incubation conditions, and microbial enumeration results, in the preservative efficacy testing log or laboratory notebook.
4.5.2 Review the preservative efficacy data and ensure all results are within the specified acceptance criteria.
4.5.3 Submit the preservative efficacy test results for review and approval by QA personnel.
4.5.4 Maintain records of the preservative efficacy test results according to company policy and regulatory requirements for future reference and audits.
5) Abbreviations, if any
QA: Quality Assurance
PPE: Personal Protective Equipment
SOP: Standard Operating Procedure
CFU: Colony-Forming Units
6) Documents, if any
Batch Records
Sampling Plan
Preservative Efficacy Testing Log
Calibration Records
7) Reference, if any
USP (United States Pharmacopeia) General Chapter 51: Antimicrobial Effectiveness Testing
ICH Q6A: Specifications: Test Procedures and Acceptance Criteria for New Drug Substances and New Drug Products: Chemical Substances
8) SOP Version
Version 1.0
