Procedure for pH Determination in Semisolids

1) Purpose

The purpose of this SOP is to outline the procedure for determining the pH of semisolid pharmaceutical formulations to ensure their quality and consistency.

2) Scope

This SOP applies to all semisolid formulations (e.g., creams, ointments, gels) manufactured within the facility that require pH determination as part of quality control testing.

3) Responsibilities

Quality Control (QC) Department: Responsible for conducting pH determination and ensuring compliance with this SOP.
Production Department: Responsible for providing semisolid samples and supporting QC during testing.

4) Procedure

4.1 Equipment Preparation:
    4.1.1 Verify and calibrate the pH meter and electrodes according to the manufacturer’s instructions.
    4.1.2 Ensure adequate supply of calibration buffers (pH 4.0, pH 7.0, pH 10.0) and distilled water.
    4.1.3 Perform pH meter suitability checks using standard solutions before testing.

4.2 Sample Preparation:
    4.2.1 Obtain representative samples of semisolid formulations from different batches.
    4.2.2 Mix samples thoroughly to ensure homogeneity before pH measurement.
    4.2.3 Allow samples to equilibrate to room temperature if necessary.

4.3 pH Measurement:
    4.3.1 Calibrate the pH meter using standard pH buffers (pH 4.0, pH 7.0, pH 10.0) before each measurement session.
    4.3.2 Immerse the pH electrode into the sample without touching the container walls.
    4.3.3 Record the