Procedure for Refractive Index Testing
1) Purpose
The purpose of this SOP is to outline the procedure for determining the refractive index of pharmaceutical liquids using appropriate analytical techniques.
2) Scope
This SOP applies to all pharmaceutical liquids within the facility that require refractive index testing as part of quality control, following pharmacopeial guidelines and internal specifications.
3) Responsibilities
Quality Control (QC) Department: Responsible for performing refractive index testing and ensuring compliance with this SOP.
Analytical Laboratory: Responsible for conducting analysis using suitable techniques and interpreting results accurately.
4) Procedure
4.1 Instrument Preparation:
4.1.1 Ensure the refractometer is calibrated according to manufacturer instructions and method validation protocols.
4.1.2 Verify the cleanliness and condition of the instrument prism and sample chamber.
4.1.3 Stabilize the instrument at the specified temperature for accurate measurements.
4.2 Sample Handling:
4.2.1 Obtain representative samples of pharmaceutical liquids requiring refractive index analysis.
4.2.2 Label samples with batch numbers, dates, and any other relevant information.
4.2.3 Ensure samples are at the specified temperature for analysis to minimize temperature-related errors.
4.3 Measurement Procedure:
4.3.1 Place a drop of the sample on the refractometer prism and close the cover gently to avoid air bubbles.
4.3.2 Allow sufficient time for the sample to equilibrate with the prism temperature and achieve stable readings.
4.3.3 Record the refractive index value displayed on the instrument, ensuring accurate reading and notation of any adjustments.
4.4 Calibration Verification:
4.4.1 Periodically verify the accuracy of the refractometer by measuring certified reference standards with known refractive indices.
4.4.2 Document calibration verification results and adjust instrument settings if deviations are observed.
4.4.3 Maintain records of calibration checks to ensure ongoing accuracy and traceability.
4.5 Calculation and Documentation:
4.5.1 Calculate and report the average refractive index value based on repeated measurements.
4.5.2 Document all refractive index testing procedures, instrument settings, and results in the Refractive Index Testing Report.
4.5.3 Review and approve the documentation by QC Manager before releasing results.
5) Abbreviations, if any
QC: Quality Control
6) Documents, if any
Refractive Index Testing Report
Instrument Calibration Records
Method Validation Protocol and Report
7) Reference, if any
USP General Chapter <831> – Refractive Index
Pharmacopeial standards for refractive index determination in pharmaceutical liquids
8) SOP Version
Version 1.0
