Standard Operating Procedure for Monitoring Coating Uniformity in Film-Coated Tablets

Department	Quality Control
SOP No.	SOP/TAB/124/2025
Supersedes	SOP/TAB/124/2022
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 monitoring the uniformity of the coating process in film-coated tablets to ensure that tablets meet the required coating specifications for quality, consistency, and appearance.

2. Scope

This SOP applies to the monitoring of coating uniformity during the film-coating process, ensuring that the tablets achieve a uniform and consistent coating throughout the production batch.

3. Responsibilities

• Quality Control (QC): Responsible for monitoring the coating process and conducting tests to verify the uniformity of the tablet coatings.
• Coating Operator: Responsible for carrying out the coating process and ensuring that the coating is uniform during production. They must also adjust parameters to maintain coating consistency.
• Quality Assurance (QA): Reviews the coating uniformity monitoring records and ensures compliance with product specifications and regulatory requirements.

4. Accountability

The QC Manager is accountable for ensuring that the coating uniformity is monitored accurately and in accordance with this SOP. The QA Manager is responsible for reviewing records and ensuring that the coating uniformity meets regulatory and internal standards.

5. Procedure

5.1 Sample Collection

1. During the coating process, collect a representative sample of tablets at regular intervals, typically every 15 minutes or after processing every 100 tablets.
2. The sample size should be sufficient to ensure reliable results, usually a minimum of 10 tablets per sample.

5.2 Visual Inspection for Coating Uniformity

1. Inspect the collected sample for visual uniformity of the coating, including color, thickness, and evenness across all tablets.
2. Check for defects such as color variation, incomplete coating, or excessive coating in any areas.
3. If the coating is not uniform, document the issue and investigate potential causes, such as spray rate, drying time, or other process parameters.

5.3 Thickness Measurement of Coated Tablets

1. Measure the coating thickness at multiple points on each tablet using a calibrated coating thickness gauge.
2. Ensure that the gauge is properly calibrated before taking measurements.
3. Record the coating thickness of each tablet and calculate the average coating thickness of the sample.
4. The coating thickness should be consistent across all tablets, with deviations not exceeding the predefined acceptable limits (e.g., ±10% of target thickness).

5.4 In-Process Adjustments

1. If the coating uniformity falls outside the acceptable limits, adjust the coating process parameters, such as spray rate, drying temperature, or tablet rotation speed.
2. After making adjustments, re-sample and re-inspect the tablets for coating uniformity.
3. Continue to monitor the coating process until the tablets meet the required uniformity specifications.

5.5 Monitoring Frequency

1. Coating uniformity should be monitored at regular intervals throughout the coating process. Typically, checks are made every 15 minutes or after coating a set number of tablets (e.g., every 100 tablets).
2. Additional checks should be made if any irregularities or deviations are observed during the process.

5.6 Documentation

1. Record the following information during each monitoring interval:
   • Sample number and time of collection
   • Visual inspection results (color, coating completeness, and appearance)
   • Coating thickness measurements and average thickness
   • Deviation from target coating thickness, if any
   • Corrective actions taken
2. Document all deviations and corrective actions in the deviation report (Annexure-1).
3. Ensure that all records are signed, dated, and reviewed by QA for compliance.

5.7 Acceptance Criteria

1. The coating should be uniform, with no visible defects such as color variation or incomplete coating.
2. Coating thickness should be consistent across all tablets, with a maximum acceptable deviation of ±10% of the target thickness.
3. If the coating uniformity or thickness falls outside the acceptable limits, the batch may be rejected or reprocessed, and corrective actions should be documented in the deviation report (Annexure-1).

5.8 Post-Coating Actions

1. Once coating uniformity is confirmed, proceed with the next steps in tablet production, including drying, packaging, or storage.
2. Ensure that any adjustments made to the coating process are recorded, and that the equipment is cleaned and calibrated as required.

6. Abbreviations

• SOP: Standard Operating Procedure
• GMP: Good Manufacturing Practice
• QC: Quality Control
• QA: Quality Assurance
• API: Active Pharmaceutical Ingredient

7. Documents

1. Batch Record (Annexure-2)
2. Deviation Report (Annexure-1)

8. References

• USP <1231> – Coating Uniformity of Tablets
• 21 CFR Part 211 – Current Good Manufacturing Practice for Finished Pharmaceuticals (US FDA)
• European Pharmacopoeia (EP) – Tablet Coating Specifications

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	Uneven coating on 5% of tablets	Adjusted spray rate and re-tested	Jane Smith

Annexure-2: Batch Record

Sample Number	Visual Inspection Results	Coating Thickness (µm)	Average Thickness (µm)	Deviation (%)	Action Taken
Sample 1	No defects	35	34	±2.5%	Accepted

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 inspection criteria	Refined coating uniformity monitoring	QA Head