Standard Operating Procedure for Adhesion Testing of Enteric Coating During Coating
| Department | Tablet |
|---|---|
| SOP No. | SOP/TAB/167/2025 |
| Supersedes | SOP/TAB/167/2022 |
| Page No. | Page 1 of 6 |
| Issue Date | 01/03/2026 |
| Effective Date | 06/03/2026 |
| Review Date | 01/03/2027 |
1. Purpose
To define the procedure for performing adhesion testing of enteric coating during the coating process of tablets, ensuring that the enteric coating adheres properly to the tablet core and meets quality standards.
2. Scope
This SOP applies to the adhesion testing of enteric coatings during the film coating process, ensuring that the coating adheres uniformly to the tablet surface and provides adequate protection as specified in the batch record.
3. Responsibilities
- Production Operator: Responsible for performing the adhesion testing during the enteric coating process and ensuring that the coating adheres properly to the tablets.
- Quality Control (QC): Responsible for verifying the adhesion testing process, reviewing the results, and ensuring the quality of the enteric coating.
- Quality Assurance (QA): Ensures that the adhesion testing process is performed as per this SOP and reviews the documentation for compliance with GMP standards.
4. Accountability
The Production Supervisor is accountable for ensuring that the adhesion testing is performed at the correct stages of the coating process. The QC Manager is responsible for ensuring the results are within acceptable limits and reviewing any deviations or failures.
5. Procedure
5.1 Preparation for Adhesion Testing
- Ensure that the enteric coating pan is set up and calibrated correctly, with the proper coating solution prepared according to the batch record.
- Check that the tablets are prepared and ready for coating, following the established protocol for the tablet’s core preparation.
- Verify that the equipment and tools required for adhesion testing, such as test devices, magnifying glasses, and adhesion test standards, are available and ready for use.
- Ensure that all necessary records are available, including the batch record, test methods, and specifications for adhesion strength.
5.2 Performing Adhesion Testing
- During the coating process, take a representative sample of the tablets after the enteric coating has been applied but before the final curing stage.
- Perform the adhesion test on the coated tablets using the approved test method (e.g., tape test, scratch test, or peel test) to check the strength of the bond between the tablet core and the enteric coating.
- For the tape test, apply a piece of adhesive tape to the coated tablet and then peel it off. Inspect the tablet’s surface to check if the coating adheres properly without any peeling or flaking.
- For the scratch or peel test, use a calibrated test device to scratch or peel a small section of the coating and observe the results for proper adhesion.
- Document the results of the adhesion test, including the method used, the time of testing, and the results (pass/fail) in the batch record (Annexure-2).
5.3 Verifying Adhesion Test Results
- Review the adhesion test results to ensure that the coating adheres properly to the tablet core, with no signs of detachment, cracking, or peeling.
- Ensure that the adhesion strength meets the specified limits defined in the batch record and product specifications.
- If the adhesion test results pass, document the results and proceed with the next step in the coating process (e.g., curing, drying, or packaging).
- If the adhesion test fails, document the failure in the deviation report (Annexure-1) and initiate corrective actions.
5.4 Corrective Actions for Adhesion Failures
- If the adhesion test fails, investigate the possible causes, such as improper coating solution, incorrect application technique, insufficient curing, or defects in the tablet core.
- Adjust the coating parameters, such as the application method, solution concentration, or curing time, and reapply the enteric coating to the tablets.
- Re-test the adhesion after the corrective actions are made and verify that the coating adheres properly to the tablet.
- Document all corrective actions taken in the deviation report and ensure that they are reviewed by QA before proceeding with the next stage of manufacturing.
5.5 Acceptance Criteria
- The batch is considered acceptable if the enteric coating passes the adhesion test, with no signs of peeling, cracking, or inadequate adhesion to the tablet core.
- If the adhesion test fails, corrective actions must be taken, and re-testing must be performed. The batch may not proceed to the next stage until the adhesion test passes.
5.6 Post-Testing Actions
- If the adhesion test passes, document the results in the batch record and proceed with the next steps in the tablet manufacturing process, such as drying or packaging.
- If the test fails and corrective actions are taken, repeat the adhesion testing until the coating passes the required adhesion strength.
- Ensure that all records and documentation are completed and retained according to the company’s document retention policy.
6. Abbreviations
- SOP: Standard Operating Procedure
- GMP: Good Manufacturing Practice
- QC: Quality Control
- QA: Quality Assurance
- API: Active Pharmaceutical Ingredient
- CAPA: Corrective and Preventive Action
7. Documents
- Batch Record (Annexure-2)
- Deviation Report (Annexure-1)
8. References
- USP <701> – Film Coating Specifications
- 21 CFR Part 211 – Current Good Manufacturing Practice for Finished Pharmaceuticals (US FDA)
- European Pharmacopoeia (EP) – Guidelines for Coating Process and Adhesion Testing
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Deviation Report
| Deviation Date | Batch Number | Deviation Description | Corrective Action | Responsible Person |
|---|---|---|---|---|
| 15/12/2025 | Batch 001 | Coating failed adhesion test | Adjusted coating solution and re-applied coating | John Doe |
Annexure-2: Batch Record
| Sample Number | Adhesion Test Result | Tested By |
|---|---|---|
| Sample 1 | Pass | Jane Smith |
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 adhesion testing procedure | Improved testing method | QA Head |