Standard Operating Procedure for Enteric Coating Process Optimization

Department	Tablet
SOP No.	SOP/TAB/013/2025
Supersedes	SOP/TAB/013/2022
Page No.	Page 1 of 8
Issue Date	14/04/2025
Effective Date	19/04/2025
Review Date	14/04/2026

1. Purpose

This SOP outlines the procedure for optimizing the enteric coating process to ensure that tablets are coated uniformly, effectively, and meet the specified release profile under acidic conditions.

2. Scope

This SOP applies to the enteric coating process in tablet manufacturing, including the preparation of coating solutions, machine setup, process monitoring, and quality control.

3. Responsibilities

• Manufacturing Personnel: Responsible for setting up the coating machine, applying the enteric coating, and following process parameters during the coating application.
• Quality Control (QC): Ensures that the enteric coating process is consistent with the required specifications for coating thickness, uniformity, and film integrity.
• Quality Assurance (QA): Ensures that the enteric coating process complies with regulatory and internal quality standards, reviewing records and approving any corrective actions when required.

4. Accountability

The Production Manager is accountable for ensuring that the enteric coating process is correctly implemented. The QA Manager ensures compliance with this SOP and approves any changes to the process.

5. Procedure

5.1 Preparation of Enteric Coating Solution

1. Prepare the enteric coating solution by mixing the enteric polymers (e.g., Hydroxypropyl Methylcellulose Phthalate, Eudragit) with an appropriate solvent, such as a mixture of water and ethanol.
2. Ensure that the mixture is homogeneous and free from lumps. Use a high-shear mixer if necessary to achieve uniform dispersion of the polymer.
3. Adjust the viscosity of the coating solution according to the formulation requirements, ensuring it is suitable for the coating machine being used.
4. Filter the solution to remove any particulates that could clog the spray nozzles or affect the quality of the coating.

5.2 Coating Machine Setup

1. Ensure that the coating machine is clean, calibrated, and free of any residue from previous batches.
2. Verify that the tablet drum is properly aligned and secure, ensuring that tablets will tumble evenly during the coating process.
3. Set up the spray nozzles according to the specifications for the enteric coating solution, ensuring uniform spraying and accurate application of the coating material.
4. Adjust the air pressure, temperature, and spray rate based on the properties of the enteric coating solution and the desired film thickness.

5.3 Loading Tablets into the Coating Drum

1. Ensure that tablets are free from defects (e.g., chips, cracks) before loading them into the coating drum.
2. Load the tablets evenly into the drum, ensuring they are not overcrowded to allow for optimal tumbling and coating distribution.
3. Ensure the drum is rotating at the correct speed to achieve an even coating distribution.

5.4 Enteric Coating Process

1. Start the coating machine and allow the tablets to tumble in the coating drum.
2. Begin introducing the enteric coating solution into the spray system gradually while adjusting the spray rate to achieve uniform coating coverage.
3. Ensure that the temperature and airflow settings remain constant during the process to maintain optimal coating conditions and prevent solvent evaporation.
4. Monitor the tablets for coating uniformity, making sure they are evenly coated without over-spraying, which can lead to uneven coating thickness or defects.
5. Continue the coating process until the desired coating thickness is achieved. Verify the thickness using appropriate measuring tools (e.g., coating thickness gauge).

5.5 In-Process Quality Control

1. Monitor the coating process by performing regular checks on the tablets for uniformity, appearance, and coating thickness.
2. Check for any defects such as uneven coating, peeling, or cracking. If any defects are detected, adjust the machine settings (e.g., spray rate, temperature, air pressure) to correct the issue.
3. Record the results of all in-process quality checks in the batch record (Annexure-1).

5.6 Drying Process

1. Ensure that tablets are dried adequately after coating to remove residual solvents and prevent any tackiness between tablets.
2. Monitor the drying time and temperature to ensure the tablets are not overheated, which could cause coating degradation.
3. Perform moisture content testing on the tablets to confirm they have been dried to the required levels. Ensure that the moisture content is consistent with the formulation requirements.

5.7 Post-Coating Inspection

1. Once the enteric coating process is complete, visually inspect the tablets for uniformity and coating defects (e.g., cracking, peeling).
2. Ensure that the coating thickness is consistent and meets the specification for enteric coating.
3. Perform additional quality control tests, such as pH resistance and adhesion tests, to ensure the integrity of the enteric coating.

5.8 Equipment Shutdown and Cleaning

1. After the coating process is completed, shut down the machine and clean all parts that came into contact with the enteric coating solution (e.g., spray nozzles, tablet drum).
2. Ensure that the coating equipment is thoroughly cleaned to avoid contamination between batches and prevent any cross-contamination.
3. Record all cleaning activities in the equipment cleaning log (Annexure-2).

5.9 Documentation and Record-Keeping

1. Document all steps of the enteric coating process, including solution preparation, machine setup, process monitoring, and final inspection, in the batch record.
2. Ensure that all records are reviewed, signed off, and stored for regulatory compliance and future reference.
3. Document any deviations from the standard process and corrective actions taken in the batch record.

6. Abbreviations

• SOP: Standard Operating Procedure
• GMP: Good Manufacturing Practice
• QC: Quality Control
• QA: Quality Assurance
• CoA: Certificate of Analysis

7. Documents

1. Coating Batch Record (Annexure-1)
2. Cleaning Log (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: Coating Batch Record

Batch Number	Tablet Type	Coating Solution	Spray Rate	Tablet Weight	Coating Thickness	Remarks
Batch 001	Tablet A	Enteric Coating	6 g/min	500 mg	25 µm	Within specifications
Batch 002	Tablet B	Enteric Coating	7 g/min	510 mg	30 µm	Minor adjustment needed

Annexure-2: Cleaning Log

Equipment	Cleaning Date	Cleaning Method	Personnel
Coating Machine 1	13/04/2025	Washing with detergent and rinsing with water	John Doe
Coating Machine 2	14/04/2025	Washing with detergent and rinsing with water	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 Coating Process Parameters	Optimization of Enteric Coating	QA Head