development. It ensures that the analytical method is specific and suitable for the intended use without false positives or overlapping peaks.

2. Scope

This procedure applies to all chromatographic and spectrophotometric analytical methods being developed, verified, or validated within the Analytical Method Development (AMD) department involving complex matrices or excipients.

3. Responsibilities

• Analyst: Prepare and inject blank and placebo samples, observe and document responses.
• Method Developer: Analyze data, compare against standard peaks, and suggest refinements.
• QA Reviewer: Verify all records and reports for completeness and compliance.

4. Accountability

The Section Head of Analytical Method Development is responsible for ensuring that all procedures related to placebo and blank interference evaluations are followed as per regulatory and internal standards.

5. Procedure

5.1 Preparation of Blank and Placebo

1. Prepare blank using solvent or mobile phase without API or excipients.
2. Prepare placebo formulation containing all excipients, preservatives, and additives but excluding the active pharmaceutical ingredient (API).
3. Use the same batch of excipients used in formulation trials to reflect realistic matrix interferences.

5.2 Instrumental Evaluation

1. Ensure the instrument is calibrated and ready for analysis.
2. Inject blank sample and record baseline for UV or chromatographic response.
3. Inject placebo sample and analyze for any peaks, drifts, or absorbance signals in the region of interest.
4. Compare retention times and peak shapes with standard and sample chromatograms.

5.3 Specificity Evaluation Criteria

1. No significant peak (≥0.2% of API area or ≥0.05 AU absorbance) should be present at API retention time.
2. Any observed peak in placebo or blank must not interfere with quantification or system suitability criteria.
3. If interference exists, method modification (e.g., change in wavelength, column, gradient) must be considered.

5.4 Documentation

1. Document blank and placebo preparation details, batch numbers, and quantities used in Annexure-1.
2. Attach chromatograms, absorbance spectra, and peak tables to Annexure-2.
3. Fill out evaluation form indicating presence/absence of interference, remarks, and analyst signature (Annexure-3).

5.5 Investigation and Corrective Action

1. If placebo interference is observed, perform root cause analysis considering excipient compatibility, solvent system, and column selection.
2. Modify method parameters as needed to enhance specificity (e.g., wavelength selection, mobile phase composition).
3. Repeat analysis post-modification to confirm elimination or resolution of interfering peak.

5.6 Approval and Archiving

1. Submit completed report to AMD Section Head and QA for review and approval.
2. Store electronic and hard copies of chromatograms and interference evaluations in project folder with version control.

6. Abbreviations

• API: Active Pharmaceutical Ingredient
• UV: Ultraviolet
• AUC: Area Under Curve
• QA: Quality Assurance
• AMD: Analytical Method Development

7. Documents

1. Blank/Placebo Preparation Sheet – Annexure-1
2. Chromatogram and Spectrum Set – Annexure-2
3. Interference Evaluation Form – Annexure-3

8. References

• ICH Q2(R1) – Validation of Analytical Procedures
• USP General Chapter <1225> – Validation of Compendial Procedures
• EMA Guideline on Bioanalytical Method Validation

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Sweta Rani	Priya Nair	Dr. Harshita Goyal
Designation	AMD Scientist	QA Reviewer	Head – Analytical Method Development
Department	Analytical Method Development	Quality Assurance	Analytical Method Development

11. Annexures

Annexure-1: Blank/Placebo Preparation Sheet

Details of blank and placebo composition, batch numbers of excipients, preparation date, analyst name, and storage conditions.

Annexure-2: Chromatogram and Spectrum Set

Includes baseline chromatogram for blank, placebo chromatogram, and overlay comparison with standard to visually confirm absence of interference.

Annexure-3: Interference Evaluation Form

Sample	Observed Peaks	Retention Time	Area (%)	Interference	Remarks
Placebo	None	—	—	No	Complies

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
01/06/2025	2.0	Added specificity acceptance threshold and updated annexure formats	Regulatory alignment	Dr. Harshita Goyal
15/08/2022	1.0	Initial release	New SOP	QA Head