Standard Operating Procedure for pH Testing in Cream Manufacturing
1) Purpose
The purpose of this SOP is to outline the steps required for pH testing of creams in a pharmaceutical manufacturing setting to ensure the product meets specified pH requirements.
2) Scope
This SOP applies to all personnel involved in pH testing of creams within the pharmaceutical production facility. It covers procedures for sample preparation, calibration of pH meter, and pH measurement.
3) Responsibilities
It is the responsibility of the quality control (QC) team to follow this SOP accurately and ensure that all pH tests comply with GMP standards. The QC supervisor is responsible for overseeing the pH testing process and ensuring proper documentation.
4) Procedure
4.1 Equipment Setup
4.1.1 Ensure that the pH meter is clean and calibrated according to the manufacturer’s instructions using standard buffer solutions (pH 4.0, 7.0, and 10.0).
4.1.2 Verify that the temperature compensation feature of the pH meter is functioning correctly.
4.2 Sample Preparation
4.2.1 Allow the cream sample to equilibrate to room temperature if stored under refrigerated conditions.
4.2.2 Mix the sample thoroughly to ensure homogeneity.
4.2.3 Transfer an appropriate amount of cream sample into a clean beaker.
4.3 pH Measurement
4.3.1 Immerse the pH electrode into the cream sample without touching the bottom
4.3.2 Stir gently and allow the pH reading to stabilize on the meter display.
4.3.3 Record the pH reading once stable and repeat the measurement at least three times for each sample.
4.4 Calibration Check
4.4.1 Check the calibration of the pH meter using fresh buffer solutions before starting pH measurements and after completing measurements for each batch of samples.
4.4.2 Adjust the pH meter if necessary based on the calibration check results.
4.5 Data Analysis and Acceptance Criteria
4.5.1 Compare the pH measurements against the specified acceptance criteria defined in the product specification or regulatory guidelines.
4.5.2 Record all pH test results in the batch record and electronic database.
4.5.3 Document any deviations from the acceptance criteria and notify the QC supervisor for further investigation.
4.6 Cleaning and Maintenance
4.6.1 Clean the pH meter electrode with distilled water after each use and store it in the recommended storage solution.
4.6.2 Perform routine maintenance and calibration of the pH meter as per the manufacturer’s instructions and the maintenance schedule.
4.6.3 Record all cleaning and maintenance activities in the equipment logbook.
5) Abbreviations, if any
GMP: Good Manufacturing Practices
QC: Quality Control
6) Documents, if any
Batch Manufacturing Record (BMR)
pH Testing Logbook
7) Reference, if any
ICH Q7: Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients
USP (United States Pharmacopeia) General Chapter 791: pH
8) SOP Version
Version 1.0
