specified range. The QA Manager is responsible for approving the results and ensuring compliance with regulatory standards.

5. Procedure

5.1 Preparation of Coating Solution

1. Prepare the enteric-coating solution according to the formulation and the coating process specifications.
2. Ensure all required excipients and materials are available and properly mixed to prepare the coating solution.
3. Before adjusting the pH, check the initial pH of the solution using a calibrated pH meter.

5.2 pH Adjustment

1. If the pH is outside the desired range, adjust the pH using appropriate acid or alkali solutions (e.g., citric acid, sodium hydroxide) to bring the solution into the specified pH range for enteric coating (typically pH 4.5–5.5, but as per formulation requirements).
2. Stir the solution continuously to ensure uniform distribution of the pH-adjusting agents.
3. After each addition, measure the pH again using the calibrated pH meter until the target pH is achieved.

5.3 pH Verification

1. Once the target pH is reached, verify the pH level with multiple readings from different areas of the coating solution.
2. Record the final pH value in the batch record (Annexure-1).
3. If the pH remains stable and within the acceptable range, proceed with the coating process. If not, re-evaluate the solution and repeat the pH adjustment process.

5.4 Documentation and Record-Keeping

1. Document all pH adjustments and final pH values in the batch record (Annexure-1), including the reagents used and the amounts added during pH adjustment.
2. Ensure that all records are signed, dated, and stored according to the company’s record retention policy for future audits and inspections.

5.5 Post-Adjustment Actions

1. Once the pH is adjusted and documented, proceed with the coating process or store the solution as per the process requirements.
2. Dispose of any pH adjustment reagents according to the company’s waste disposal procedures.

6. Abbreviations

• SOP: Standard Operating Procedure
• GMP: Good Manufacturing Practice
• QC: Quality Control
• QA: Quality Assurance
• pH: Potential of Hydrogen

7. Documents

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

8. References

• USP <1225> – Pharmaceutical Dosage Forms: Coating
• 21 CFR Part 211 – Current Good Manufacturing Practice for Finished Pharmaceuticals (US FDA)
• European Pharmacopoeia (EP) – Coating Material 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: Batch Record

Batch Number	Coating Solution pH	Reagents Used	Amount Added	Final pH	Remarks
Batch 001	4.2	Citric acid	50 mL	4.8	Pass

Annexure-2: Deviation Report

Deviation Date	Batch Number	Deviation Description	Corrective Action	Responsible Person
15/12/2025	Batch 001	pH adjustment exceeded limit	Re-adjusted pH to 4.8	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 pH adjustment procedure	Refined reagent usage for pH control	QA Head