Procedure for pH Determination in Topical Preparations
1) Purpose
The purpose of this SOP is to outline the procedure for determining pH in topical preparations to ensure they meet specified pH range requirements.
2) Scope
This SOP applies to all types of topical preparations requiring pH determination as part of quality control measures to assess product performance and adherence to specifications.
3) Responsibilities
Quality Control (QC) Department: Responsible for performing pH determination testing.
Quality Assurance (QA) Department: Responsible for review and approval of pH determination testing procedures and results.
Manufacturing Department: Responsible for providing topical preparation samples and support during testing.
4) Procedure
4.1 Sample Preparation:
4.1.1 Ensure topical preparation samples are well-mixed and representative of the batch.
4.1.2 Use a clean, calibrated pH meter and electrodes suitable for measuring pH in viscous solutions.
4.2 Calibration of pH Meter:
4.2.1 Calibrate the pH meter using standard pH buffers (pH 4.0, 7.0, and 10.0) before starting testing.
4.2.2 Verify the accuracy of the pH meter readings against calibration standards.
4.3 pH Measurement:
4.3.1 Immerse the pH electrode into the topical preparation sample without touching the container walls.
4.3.2 Allow the pH reading to stabilize and record the pH value.
4.4 Measurement Reproducibility:
4.4.1 Repeat pH measurements on different spots of the same sample to confirm reproducibility.
4.4.2 Ensure agreement in pH measurements within acceptable tolerance limits.
4.5 Cleaning and Maintenance:
4.5.1 Rinse the pH electrode with distilled water between measurements to prevent cross-contamination.
4.5.2 Store the pH meter and electrodes properly after use as per manufacturer instructions.
4.6 Data Recording:
4.6.1 Record pH measurement values, calibration details, and any deviations observed during testing.
4.6.2 Document all pH measurement results accurately in the appropriate records.
4.7 Reporting:
4.7.1 Prepare a pH Determination Testing Report summarizing test procedures, results, and conclusions.
4.7.2 Include any corrective actions or recommendations based on pH determination testing findings.
4.7.3 Submit the report to QA for review and approval and maintain records as per facility procedures.
5) Abbreviations, if any
QC: Quality Control
QA: Quality Assurance
6) Documents, if any
pH Determination Testing Report
Calibration Records
Sample Testing Records
7) Reference, if any
USP (insert appropriate reference for topical preparations)
FDA Guidance for Industry – Container Closure Systems for Packaging Human Drugs and Biologics
8) SOP Version
Version 1.0