Tablets: SOP for Direct Compression Blend Homogeneity Testing – V 2.0

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Tablets: SOP for Direct Compression Blend Homogeneity Testing – V 2.0

Standard Operating Procedure for Direct Compression Blend Homogeneity Testing

Department Tablet
SOP No. SOP/TAB/062/2025
Supersedes SOP/TAB/062/2022
Page No. Page 1 of 6
Issue Date 20/12/2025
Effective Date 25/12/2025
Review Date 20/12/2026

1. Purpose

The purpose of this Standard Operating Procedure (SOP) is to outline the process for testing the homogeneity of the blend used in the direct compression process. The objective is to ensure that the blend is uniformly mixed to ensure uniformity of the active pharmaceutical ingredient (API) in the final tablet dosage form.

2. Scope

This SOP applies to the testing of blend homogeneity during the direct compression process in tablet manufacturing. It includes procedures for sampling, testing, and ensuring that the blend meets uniformity criteria for weight, API content, and blend consistency.

3. Responsibilities

  • Manufacturing Personnel: Responsible for preparing the direct compression blend, ensuring that the blend is mixed according to the established process, and providing samples for homogeneity testing.
  • Quality Control (QC): Responsible for conducting the homogeneity tests, analyzing the results, and confirming whether the blend meets the required homogeneity specifications. QC will also take corrective actions if necessary.
  • Quality Assurance (QA): Ensures compliance with this SOP, reviews test results, and approves the batch if the blend homogeneity meets specifications.
  • Production Supervisor: Ensures that all personnel follow the correct procedures for blending and testing homogeneity, and addresses any deviations in the process.
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4. Accountability

The Production Manager is accountable for overseeing the blend homogeneity process during direct compression and ensuring the homogeneity of the blend. The QA Manager is responsible for reviewing the test results and ensuring that the process complies with the specifications.

5. Procedure

5.1 Preparation of Blend for Compression

  1. Ensure that all ingredients required for the blend are weighed accurately as per the batch record and formulation.
  2. Blend the ingredients using the appropriate mixing equipment (e.g., V-blender or high-shear mixer) to achieve a homogeneous blend with uniform distribution of the active pharmaceutical ingredient (API) and excipients.
  3. Check the blend for any signs of segregation or clumping, and perform additional mixing if necessary to ensure uniformity.
  4. Once the blend is ready, proceed with the sampling for homogeneity testing.

5.2 Sampling for Homogeneity Testing

  1. Take samples from different locations of the blend to ensure uniformity. Typically, samples should be taken from at least three different spots in the blend, including the top, middle, and bottom of the batch.
  2. Ensure that the sampling procedure is random and covers the entire blend to account for any potential segregation.
  3. Each sample should be of sufficient size to allow for representative testing of both the API content and other blend characteristics.
  4. Store the samples in a clean, contamination-free container until they are tested.

5.3 Blend Homogeneity Testing

  1. Conduct a uniformity of content test to determine the consistency of the API in the blend. This can be done by analyzing the API concentration in the sample using a validated analytical method, such as High-Performance Liquid Chromatography (HPLC) or UV-Visible Spectrophotometry.
  2. Check the blend for other critical properties such as flowability, moisture content, and particle size distribution, which can affect homogeneity.
  3. Ensure that the test results fall within the established specifications for API content uniformity. The allowable variation for the API content should be specified in the batch record or formulation sheet.
  4. If any sample fails the test for uniformity, repeat the blending process and retest the blend until uniformity is achieved.
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5.4 Documentation of Results

  1. Document all homogeneity testing results, including the sample locations, test methods used, and the test outcomes in the batch record (Annexure-1).
  2. Record any deviations or failures, along with corrective actions taken, in the deviation report (Annexure-2).
  3. Store all documentation in compliance with the company’s record retention policy and ensure it is accessible for audits and inspections.

5.5 Corrective Actions for Deviations

  1. If the blend fails the homogeneity test, investigate the root cause of the failure. Possible causes may include improper mixing time, inadequate mixing speed, or issues with raw material segregation.
  2. Implement corrective actions such as adjusting mixing parameters, using different excipients, or re-blending the batch if needed.
  3. Retest the batch after corrective actions have been implemented to confirm that the blend now meets the homogeneity specifications.
  4. Record the investigation findings and corrective actions in the deviation report (Annexure-2) and batch record (Annexure-1).

5.6 Calibration and Maintenance of Testing Equipment

  1. Ensure that all analytical equipment used for testing blend homogeneity, such as HPLC, UV spectrophotometers, and balances, is properly calibrated and maintained according to the manufacturer’s specifications.
  2. Document all calibration and maintenance activities in the equipment maintenance log (Annexure-3).
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6. Abbreviations

  • SOP: Standard Operating Procedure
  • GMP: Good Manufacturing Practice
  • QC: Quality Control
  • QA: Quality Assurance
  • API: Active Pharmaceutical Ingredient
  • HPLC: High-Performance Liquid Chromatography

7. Documents

  1. Batch Record (Annexure-1)
  2. Deviation Report (Annexure-2)
  3. Equipment Maintenance Log (Annexure-3)

8. References

  • 21 CFR Part 211 – Current Good Manufacturing Practice for Finished Pharmaceuticals (US FDA)
  • EU GMP Guidelines Part I – Basic Requirements for Medicinal Products
  • ICH Q7 – Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients

9. SOP Version

Version: 2.0

10. Approval Section

Prepared By Checked By Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Batch Record

Batch Number Sample Location API Content Test Method Comments
Batch 001 Top, Middle, Bottom 99.5% HPLC Blend homogeneous

Annexure-2: Deviation Report

Deviation Date Batch Number Deviation Description Corrective Action Responsible Person
21/12/2025 Batch 002 API content variation Re-blended batch and retested Jane Smith

Annexure-3: Equipment Maintenance Log

Maintenance Date Equipment Maintenance Performed Performed By Comments
10/12/2025 HPLC Calibration John Doe Calibration verified, no issues found

Revision History:

Revision Date Revision No. Revision Details Reason for Revision Approved By
01/01/2024 1.0 Initial Version New SOP Creation QA Head
01/02/2025 2.0 Updated Homogeneity Test Criteria Improved Test Sensitivity QA Head
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