Standard Operating Procedure for Moisture Barrier Coating for Tablets
| Department | Tablet |
|---|---|
| SOP No. | SOP/TAB/044/2025 |
| Supersedes | SOP/TAB/044/2022 |
| Page No. | Page 1 of 6 |
| Issue Date | 16/09/2025 |
| Effective Date | 21/09/2025 |
| Review Date | 16/09/2026 |
1. Purpose
This SOP outlines the procedure for applying a moisture barrier coating on tablets. The moisture barrier coating protects the tablets from environmental moisture, which can affect the stability and integrity of the tablet, particularly for moisture-sensitive ingredients.
2. Scope
This SOP applies to the production of all tablet formulations that require moisture protection during storage and transportation. It includes the preparation of the coating solution, the application process, and quality checks to ensure uniform and effective moisture barrier protection.
3. Responsibilities
- Manufacturing Personnel: Responsible for preparing and applying the moisture barrier coating and ensuring that the process is performed according to this SOP.
- Quality Control (QC): Responsible for inspecting the tablets for uniformity of the moisture barrier coating and conducting necessary tests, such as moisture uptake tests, to verify the coating’s effectiveness.
- Quality Assurance (QA): Ensures that the moisture barrier coating process is followed as per the SOP and reviews all records and documentation related to the coating process to verify compliance with quality standards.
4. Accountability
The Production Manager is accountable for overseeing the application of the moisture barrier coating. The QA Manager is responsible for ensuring that the coating process complies with internal standards and regulatory requirements, and for reviewing the associated documentation.
5. Procedure
5.1 Pre-Coating Setup
- Ensure that the tablets have been properly compressed and dried before applying the moisture barrier coating.
- Verify that the coating equipment, including the coating pan and spray guns, is clean and calibrated according to the equipment maintenance SOP.
- Prepare the moisture barrier coating solution by dissolving the required ingredients (e.g., moisture-resistant film-forming agents, plasticizers) in the specified solvent as per the formulation.
- Check the environmental conditions, including room temperature and humidity, to ensure they are within the specified range for the coating process.
5.2 Application of Moisture Barrier Coating
- Place the tablets in the coating pan, ensuring that they are evenly distributed for uniform coating.
- Set the temperature and airflow in the coating pan as per the required specifications for moisture barrier coating. The temperature should generally be between 40°C and 50°C to prevent over-drying or under-drying the coating.
- Begin applying the moisture barrier coating solution to the tablets, ensuring that the spray rate is controlled for uniform coverage. Rotate the pan to ensure even distribution of the coating material.
- Monitor the thickness of the applied coating during the process to ensure that it remains within the defined specifications. Adjust the spray rate and airflow as needed to maintain uniformity.
- Continue the coating process until the tablets achieve the required coating thickness and uniformity.
5.3 Drying and Curing
- After applying the moisture barrier coating, increase the airflow to facilitate drying. Maintain the temperature between 40°C to 50°C to ensure proper drying of the coating.
- Allow the tablets to rotate in the pan for an adequate amount of time to ensure that the moisture barrier coating has dried completely.
- Inspect the tablets during the drying process to ensure there are no signs of moisture or tackiness, which may indicate insufficient drying.
- Continue drying the tablets until the coating is completely hardened and free from residual moisture.
5.4 Quality Control Checks
- Once the coating process is complete, perform a visual inspection of the tablets to ensure that the coating is uniform and free from defects such as cracks, peeling, or uneven coverage.
- Measure the coating thickness using appropriate tools to ensure that it meets the required specifications.
- Perform moisture uptake testing on a sample of tablets to verify that the moisture barrier is functioning effectively and protecting the tablets from environmental moisture.
- Document all quality control checks, including coating thickness, visual inspection, and moisture uptake test results, in the batch record (Annexure-1).
5.5 Post-Coating Inspection
- Inspect the tablets after the coating has dried to confirm that there is no residual tackiness or unevenness in the coating.
- Ensure that the tablets have a smooth, glossy finish and that the coating adheres well to the tablet surface without any visible defects.
- Conduct hardness and friability tests to ensure that the moisture barrier coating does not compromise the mechanical strength or durability of the tablets.
- Document the results of all tests and inspections in the batch record (Annexure-1) and the deviation report (Annexure-2) if necessary.
5.6 Documentation and Record-Keeping
- Record all details of the moisture barrier coating process, including solution preparation, equipment settings, inspection results, and any deviations, in the batch record (Annexure-1).
- Document any deviations or issues encountered during the process in the deviation report (Annexure-2), along with the corrective actions taken.
- Ensure that all records are reviewed and signed off by the appropriate personnel, including QC and QA teams, to confirm that the process was completed properly.
- Store all records securely for future audits and regulatory inspections.
5.7 Equipment Cleaning and Maintenance
- After each batch, clean all equipment used in the moisture barrier coating process, including the coating pan, spray guns, and hoses, according to the equipment cleaning SOP.
- Inspect the equipment regularly for any signs of wear, damage, or contamination. Perform necessary repairs or replacements to maintain optimal performance.
6. Abbreviations
- SOP: Standard Operating Procedure
- GMP: Good Manufacturing Practice
- QC: Quality Control
- QA: Quality Assurance
- API: Active Pharmaceutical Ingredient
7. Documents
- Batch Record (Annexure-1)
- Deviation Report (Annexure-2)
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 | Tablet Type | Coating Solution | Application Parameters | Coating Quality |
|---|---|---|---|---|
| Batch 001 | Tablet A | Moisture barrier solution: 6% PVA | Temperature: 45°C, Airflow: 2.0 m³/min | Pass |
| Batch 002 | Tablet B | Moisture barrier solution: 5% HPMC | Temperature: 48°C, Airflow: 2.5 m³/min | Pass |
Annexure-2: Deviation Report
| Deviation Date | Batch Number | Deviation Description | Corrective Action | Responsible Person |
|---|---|---|---|---|
| 18/08/2025 | Batch 003 | Uneven coating observed | Adjusted spray rate and reprocessed | John Doe |
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 Coating Process | Improved Coating Efficiency | QA Head |