Standard Operating Procedure for Real-Time Monitoring of Tablet Coating Thickness
| Department | Tablet |
|---|---|
| SOP No. | SOP/TAB/026/2025 |
| Supersedes | SOP/TAB/026/2022 |
| Page No. | Page 1 of 7 |
| Issue Date | 18/06/2025 |
| Effective Date | 23/06/2025 |
| Review Date | 18/06/2026 |
1. Purpose
This SOP outlines the procedures for real-time monitoring of tablet coating thickness during the coating process, ensuring that the applied coating is within specified limits for uniformity and quality.
2. Scope
This SOP applies to the coating process in tablet manufacturing, specifically focusing on the use of real-time monitoring tools and techniques to measure coating thickness during the application process.
3. Responsibilities
- Manufacturing Personnel: Responsible for ensuring that the coating thickness is monitored in real-time and adjustments are made to the process to maintain uniform coating.
- Quality Control (QC): Conducts periodic checks to verify the coating thickness using real-time data and ensures the tablets meet the required specifications for coating.
- Quality Assurance (QA): Ensures that the real-time monitoring system is functioning properly and verifies that all process parameters are documented and within acceptable limits.
4. Accountability
The Production Manager is accountable for ensuring that real-time monitoring is implemented and that the tablet coating process is in
compliance with this SOP. The QA Manager is responsible for overseeing the monitoring system and ensuring that all data is accurately recorded.
5. Procedure
5.1 Pre-Coating Setup
- Ensure that the tablet coating machine is set up correctly and calibrated, including all monitoring systems for real-time coating thickness measurement.
- Verify that the tablet pan is clean and free from contaminants to prevent any discrepancies in the coating process.
- Prepare the coating solution according to the formulation and ensure it is properly filtered to prevent any blockages in the spray nozzles.
- Ensure that the real-time monitoring system (e.g., laser or ultrasonic sensors) is calibrated and ready for operation, ensuring that accurate data on coating thickness is recorded.
5.2 Real-Time Coating Thickness Monitoring
- Start the tablet coating process and activate the real-time monitoring system to begin measuring the coating thickness as the tablets move through the coating pan.
- Continuously monitor the data provided by the coating thickness measurement system, which should record and display the coating thickness for each tablet in real-time.
- Adjust the spray parameters (e.g., spray rate, nozzle size, air pressure) to maintain the desired coating thickness as indicated by the real-time data.
- If the coating thickness exceeds the acceptable limits (typically ±10% of the target thickness), adjust the coating process immediately to bring the thickness within specification.
- Ensure that the real-time monitoring system logs all data, including time, batch number, tablet identification, and measured coating thickness, into the batch record (Annexure-1).
5.3 In-Process Adjustments and Corrections
- If deviations in coating thickness are detected, make immediate adjustments to the coating parameters such as spray speed, solution concentration, or airflow to correct the variation.
- After making adjustments, continue monitoring the coating thickness in real-time to ensure the adjustments have brought the coating thickness back within the acceptable range.
- Record all adjustments made during the process, including the reason for the adjustment and the specific changes implemented in the batch record (Annexure-2).
5.4 Final Coating Inspection
- Once the real-time monitoring system confirms that the coating has reached the desired thickness, perform a final visual inspection of the coated tablets to ensure uniform coating and the absence of defects such as peeling or uneven application.
- Measure the coating thickness on a sample of tablets using a micrometer or coating thickness gauge to verify the data from the real-time monitoring system.
- Document the results of the final inspection and the coating thickness measurements in the batch record (Annexure-3).
5.5 Post-Coating Process
- After confirming that the desired coating thickness has been achieved, allow the tablets to dry under controlled conditions, using the drying system to prevent excess moisture that could affect tablet integrity.
- Ensure that the drying parameters are controlled to avoid over-drying or under-drying, which could impact the coating and tablet quality.
- Record all drying parameters and the results of the final coating inspection in the batch record, ensuring that all quality checks are completed before the tablets proceed to the next stage in the manufacturing process.
5.6 Equipment Shutdown and Cleaning
- After completing the coating process, shut down the equipment following the SOP for equipment shutdown and cleaning.
- Ensure that the coating pan, spray nozzles, and monitoring system are thoroughly cleaned to prevent cross-contamination during the next batch.
- Record the cleaning activities in the equipment cleaning log (Annexure-4) and ensure that all equipment is ready for the next production run.
5.7 Documentation and Record-Keeping
- Ensure that all real-time monitoring data, coating thickness measurements, and adjustments are documented in the batch record (Annexure-1).
- Review the batch records to ensure that all process parameters are within the acceptable range and that no deviations were left unaddressed.
- Ensure that all records are reviewed by QA personnel and that proper documentation is maintained for regulatory compliance and audit purposes.
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)
- Coating Thickness Monitoring Log (Annexure-2)
- Final Inspection Log (Annexure-3)
- Equipment Cleaning Log (Annexure-4)
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 Thickness (mm) | Spray Pressure (bar) | Airflow Rate (m³/hr) | Remarks |
|---|---|---|---|---|---|
| Batch 001 | Tablet A | 0.2 | 3 | 150 | Within specifications |
| Batch 002 | Tablet B | 0.25 | 3.5 | 160 | Adjustment applied |
Annexure-2: Coating Thickness Monitoring Log
| Batch Number | Tablet Type | Coating Thickness (mm) | Time | Remarks |
|---|---|---|---|---|
| Batch 001 | Tablet A | 0.2 | 12:00 PM | Within specifications |
| Batch 002 | Tablet B | 0.25 | 2:00 PM | Adjusted coating thickness |
Annexure-3: Final Inspection Log
| Batch Number | Tablet Type | Coating Thickness (mm) | Inspection Date | Remarks |
|---|---|---|---|---|
| Batch 001 | Tablet A | 0.2 | 12:30 PM | Coating uniformity verified |
| Batch 002 | Tablet B | 0.25 | 2:30 PM | Adjustment completed successfully |
Annexure-4: Equipment Cleaning Log
| Cleaning Date | Equipment | Cleaning Type | Performed By | Remarks |
|---|---|---|---|---|
| 02/05/2025 | Coating Machine | Routine Cleaning | John Doe | Performed as per SOP |
| 12/06/2025 | Coating Machine | Maintenance Cleaning | Jane Smith | 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 Monitoring Parameters | Optimization of Coating Process | QA Head |