reviewing the results and approving the batch for release.

5. Procedure

5.1 Sample Collection

1. Collect a representative sample of enteric-coated tablets from the batch, as specified in the batch record.
2. The sample should consist of 6 tablets (or as specified in the batch record or pharmacopeial guidelines).
3. Ensure that the tablets are free from defects such as cracks, chips, or visible contamination.
4. Label the sample appropriately for identification during testing.

5.2 Preparation of pH Stability Test Apparatus

1. Prepare a pH stability testing setup, including a pH meter, dissolution apparatus, and appropriate buffers.
2. Prepare the dissolution media according to the test method, which should include a buffer solution at a pH of 1.2 (simulating stomach conditions) and a buffer solution at a pH of 6.8 (simulating intestinal conditions).
3. Ensure that the dissolution apparatus is calibrated and that the test vessels are properly cleaned and maintained.

5.3 Conducting the pH Stability Test

1. Place each tablet into the dissolution vessels and immerse in the pH 1.2 buffer solution at 37°C for the specified duration (usually 2 hours).
2. After the specified time, transfer the tablets to the pH 6.8 buffer solution and continue the testing for the designated period (typically 4 hours).
3. Monitor the dissolution process, ensuring the tablets remain intact under acidic conditions and begin to disintegrate or release API once the pH shifts to 6.8.
4. At predefined intervals, sample the dissolution medium and analyze for the release of the active pharmaceutical ingredient (API) using an appropriate analytical method (e.g., UV spectrophotometry, HPLC).

5.4 Data Recording and Calculation

1. Record the pH stability testing results, including the time points and corresponding API concentrations, in the batch record (Annexure-1).
2. Calculate the cumulative percentage of the API released at each time point, ensuring the release profile meets the specifications.
3. Ensure that the tablets pass the dissolution criteria, which typically includes ≥ 80% of the API released in the pH 6.8 medium.

5.5 pH Stability Acceptance Criteria

1. Ensure that the enteric-coated tablets do not disintegrate in the acidic pH (1.2), and that they release the API only after being exposed to the pH 6.8 buffer.
2. If any tablet fails to meet the stability criteria, the batch should be investigated, and corrective actions should be documented in the deviation report (Annexure-2).

5.6 Documentation and Record-Keeping

1. Document the pH stability testing results, including the individual API release values and cumulative release, in the batch record (Annexure-1).
2. Record any deviations from the pH stability specifications in the deviation report (Annexure-2), along with the corrective actions taken.
3. Ensure that all records are signed, dated, and stored according to the company’s record retention policy for future audits and inspections.

5.7 Post-Test Cleanup

1. Clean all equipment used for pH stability testing, including dissolution vessels and pH meters, according to the manufacturer’s guidelines and the company’s cleaning SOP.
2. Ensure that all equipment is properly stored and maintained in good working condition for future use.

6. Abbreviations

• SOP: Standard Operating Procedure
• GMP: Good Manufacturing Practice
• QC: Quality Control
• QA: Quality Assurance
• API: Active Pharmaceutical Ingredient
• HPLC: High-Performance Liquid Chromatography

7. Documents

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

8. References

• USP <711> – Dissolution Test
• 21 CFR Part 211 – Current Good Manufacturing Practice for Finished Pharmaceuticals (US FDA)
• European Pharmacopoeia (EP) – Dissolution Test for Enteric-Coated Tablets

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 Sample	Time Points (min)	API Concentration (mg/mL)	Cumulative Release (%)
Batch 001	6 tablets	30	2.5	50%
Batch 001	6 tablets	60	5.0	90%

Annexure-2: Deviation Report

Deviation Date	Batch Number	Deviation Description	Corrective Action	Responsible Person
12/11/2025	Batch 001	API release out of specification	Re-formulated enteric coating	John Doe

Revision History:

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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 Testing Protocols	Improved test parameters for stability	QA Head