SOP for Angle of Repose Testing

Procedure for Angle of Repose Testing

1) Purpose

The purpose of this SOP is to outline the procedure for determining the angle of repose of pharmaceutical powders using appropriate analytical techniques.

2) Scope

This SOP applies to all pharmaceutical powders within the facility that require angle of repose testing as part of quality control, following pharmacopeial guidelines and internal specifications.

3) Responsibilities

Quality Control (QC) Department: Responsible for performing angle of repose testing and ensuring compliance with this SOP.
Analytical Laboratory: Responsible for conducting analysis using suitable techniques and interpreting results accurately.

4) Procedure

4.1 Apparatus Setup:
    4.1.1 Ensure the apparatus (e.g., funnel, protractor, flat surface) is assembled and positioned correctly.
    4.1.2 Verify the cleanliness and condition of the apparatus components.
    4.1.3 Ensure the flat surface is level and stable to prevent movement during testing.

4.2 Sample Preparation:
    4.2.1 Obtain representative samples of pharmaceutical powders requiring angle of repose testing.
    4.2.2 Label samples with batch numbers, dates, and any other relevant information.
    4.2.3 Sieve samples to remove aggregates and achieve uniform particle size distribution.

4.3 Testing Procedure:
    4.3.1 Fix the funnel at a specified height above the flat surface.
    4.3.2 Carefully pour the sample powder through the funnel until the heap of powder forms a cone.
    4.3.3 Allow the powder to flow freely until no further movement is observed.

4.4 Measurement:
4.4.1 Measure the height (h) and the radius (r) of the powder cone.
4.4.2 Calculate the angle of repose (θ) using the formula: θ = tan⁻¹(h / r).

4.5 Calculation and Documentation:
    4.5.1 Calculate and report the average angle of repose based on repeated measurements.
    4.5.2 Document all angle of repose testing procedures, instrument settings, and results in the Angle of Repose 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

Angle of Repose Testing Report
Method Validation Protocol and Report
Instrument Calibration Records

7) Reference, if any

USP General Chapter <1174> – Powder Flow
Pharmacopeial standards for angle of repose testing in pharmaceutical substances

8) SOP Version

Version 1.0