media and meets dissolution criteria in buffer media as per pharmacopeial and regulatory standards.

2. Scope

This SOP applies to the Analytical Method Development and Quality Control departments responsible for testing enteric-coated tablets or capsules during formulation development, stability studies, and batch release.

3. Responsibilities

• Analytical Scientist: Designs and validates acid resistance and buffer dissolution methods.
• QC Analyst: Conducts routine integrity testing and reports results.
• QA Executive: Reviews data and ensures regulatory compliance.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring accurate, validated, and compliant methods to verify enteric coating performance across batches.

5. Procedure

5.1 Apparatus

• USP Dissolution Apparatus I (Basket) or II (Paddle)
• Disintegration Tester (optional)
• UV-Visible Spectrophotometer or HPLC

5.2 Acid Resistance Test

1. Use 0.1N HCl as medium, 750 mL per vessel at 37 ± 0.5°C.
2. Set apparatus: Paddle at 50 rpm or Basket at 100 rpm.
3. Place 6 dosage units and run for 2 hours.
4. Check for visual disintegration or drug release (NMT 10%).
5. Collect sample at end of acid stage, filter, and analyze using UV or HPLC.

5.3 Buffer Dissolution Test

1. Add 250 mL of pre-warmed phosphate buffer (pH 6.8) to each vessel to make total volume 1000 mL.
2. Continue run as per dissolution specification (e.g., 45 or 60 minutes).
3. Withdraw samples at predetermined time points (e.g., 15, 30, 45 min).
4. Filter samples and measure absorbance at λ_max or inject into HPLC.

5.4 Evaluation and Acceptance Criteria

• Acid Stage: NMT 10% of drug should be released after 2 hours.
• Buffer Stage: NLT 80% drug should be released within specified time (typically 45 minutes).

5.5 Validation Parameters

1. Specificity: No interference in acid and buffer stage media.
2. Linearity: r² ≥ 0.999 over 50%–150% range.
3. Accuracy: Recovery 98%–102% in both stages.
4. Precision: RSD ≤ 2% at each stage.
5. Robustness: Evaluate at ±5 rpm and ±0.1 pH media variation.

6. Abbreviations

• HCl: Hydrochloric Acid
• UV: Ultraviolet
• HPLC: High Performance Liquid Chromatography
• RSD: Relative Standard Deviation

7. Documents

1. Enteric Coating Integrity Test Log – Annexure-1
2. Dissolution Profile Data – Annexure-2
3. Validation Summary Report – Annexure-3

8. References

• USP <711>: Dissolution
• ICH Q2(R1): Validation of Analytical Procedures
• FDA Guidance for Enteric-Coated Products

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Ritika Deshmukh	Vishal Patil	Sunita Reddy
Designation	Dissolution Analyst	QA Reviewer	Head – AMD
Department	Analytical Method Development	QA	Analytical Method Development

11. Annexures

Annexure-1: Enteric Coating Integrity Test Log

Sample ID	Acid Release (%)	Buffer Release (%)	Status
ECI-291-01	6.3%	91.2%	Pass

Annexure-2: Dissolution Profile Data

Time (min)	% Release
15	35%
30	68%
45	91%

Annexure-3: Validation Summary Report

The enteric coating integrity method was validated for specificity, precision, accuracy, and robustness. Results confirmed the integrity and performance of the enteric layer under simulated gastrointestinal conditions.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
21/05/2025	2.0	Updated buffer media conditions and validation acceptance criteria	Annual Review	Sunita Reddy
01/11/2022	1.0	Initial SOP Release	New SOP	QA Head