Standard Operating Procedure for Lotion pH Testing

1) Purpose

The purpose of this SOP is to outline the procedure for conducting pH testing of lotions to ensure the product maintains the desired pH range for safety and efficacy.

2) Scope

This SOP applies to all personnel involved in the pH testing of lotions within the pharmaceutical manufacturing facility.

3) Responsibilities

The responsibilities for executing this SOP are as follows:

Laboratory Analysts:

• Perform pH tests according to this SOP and document results accurately.
• Ensure all pH testing equipment is calibrated and maintained.

Quality Control Personnel:

• Review and verify pH test results for accuracy and compliance with specifications.

Quality Assurance Personnel:

• Ensure that the pH testing program complies with regulatory requirements.

4) Procedure

4.1 Pre-Testing Preparation:

• Ensure the pH meter is calibrated using standard buffer solutions (pH 4.0, 7.0, and 10.0).
• Prepare the lotion samples according to the specified sampling plan.

4.2 pH Testing Process:

1. Equipment Setup:
   • Set up the pH meter according to the manufacturer’s instructions.
   • Verify that the pH electrode is clean and in good condition.
2. Sample Preparation:
   • Stir the lotion sample gently to ensure uniformity.
   • Transfer an adequate amount of lotion into a clean, dry container.
3. Conducting the Test:
   1. Immerse the pH electrode into the lotion sample, ensuring it is fully submerged.
   2. Allow the pH meter to stabilize and display a reading.
   3. Record the pH reading displayed on the meter.
   4. Rinse the electrode with distilled water and blot dry between tests if multiple samples are being tested.
4. Post-Test Activities:
   • Clean the pH electrode and sample container thoroughly after each test.
   • Document the test results in the laboratory logbook and batch record.

4.3 Documentation:

• Record the pH readings, test conditions, and any observations in the laboratory logbook.
• Ensure all documentation is complete and accurate, including the batch number and test date.

4.4 Review and Evaluation:

• Compare the pH results with the product specifications to determine if the lotion meets the required standards.
• Document any deviations and investigate the cause.

5) Abbreviations, if any

pH: Potential of Hydrogen

6) Documents, if any

• Laboratory Logbook
• Batch Record
• pH Meter Calibration Records

7) Reference, if any

• USP <791> pH
• Manufacturer’s instructions for the specific pH meter model used

8) SOP Version

Version 1.0