quantifying residual active pharmaceutical ingredients (APIs) on equipment surfaces post-cleaning as part of the cleaning validation program.

2. Scope

This SOP applies to the Analytical Method Development (AMD) department for the development and validation of HPLC methods used in surface swab or rinse sample analysis to ensure that equipment cleaning is effective and within allowable residue limits.

3. Responsibilities

• Analytical Scientist: Develops and validates HPLC method for targeted residual API.
• QC Analyst: Performs method verification using spiked surface swabs or rinse solutions.
• QA Executive: Reviews method validation data and approves for GMP implementation.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring HPLC methods used for residue detection are scientifically justified, validated, and comply with regulatory standards.

5. Procedure

5.1 Method Development

1. Select appropriate HPLC conditions based on API properties:
   • Column: C18, 250 mm × 4.6 mm, 5 µm
   • Mobile Phase: Water:Acetonitrile (60:40 or API-specific)
   • Flow Rate: 1.0 mL/min
   • Detection: UV at API-specific wavelength (e.g., 210–280 nm)

5.2 Standard and Sample Preparation

1. Prepare standard solutions of API in mobile phase (e.g., 1.0 µg/mL to 20 µg/mL).
2. For swab recovery studies:
   • Spike known amount of API onto stainless steel coupons (e.g., SS-316, 5 cm × 5 cm)
   • Swab the surface and extract analyte using diluent (e.g., 10 mL mobile phase)

5.3 Method Validation

1. Validate as per ICH Q2(R1) guidelines:
   • Specificity: No interference at retention time of analyte
   • Linearity: Range from 1 to 20 µg/mL (r ≥ 0.999)
   • Accuracy: Recovery between 85%–115%
   • Precision: RSD ≤ 5% for repeatability
   • LOD and LOQ: Based on signal-to-noise ratio (LOD: S/N ≥ 3; LOQ: S/N ≥ 10)

5.4 Acceptance Criteria for Cleaning Validation

1. Residue levels must be below MACO limit calculated as:
   
   MACO = (TDD × Minimum Batch Size) / (Safety Factor × Maximum Daily Dose)
2. Swabbed area = typically 25 cm²; back-calculation required for entire equipment surface.

5.5 Documentation

1. Document method parameters, chromatograms, linearity data, and recovery results in validation protocol and report.
2. Include swab recovery logs, instrument calibration, and system suitability tests in Annexures.

6. Abbreviations

• HPLC: High Performance Liquid Chromatography
• API: Active Pharmaceutical Ingredient
• MACO: Maximum Allowable Carryover
• TDD: Therapeutic Daily Dose
• RSD: Relative Standard Deviation

7. Documents

1. Swab Recovery Validation Log – Annexure-1
2. Linearity and Calibration Data – Annexure-2
3. HPLC Method Validation Report – Annexure-3

8. References

• ICH Q2(R1): Validation of Analytical Procedures
• FDA Guidance for Industry: Cleaning Validation
• USP <1225>: Validation of Compendial Procedures

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Vikram Patel	Anjali Rawat	Sunita Reddy
Designation	Analytical Scientist	QA Reviewer	Head – AMD
Department	Analytical Method Development	QA	Analytical Method Development

11. Annexures

Annexure-1: Swab Recovery Validation Log

Analyte	Surface	Spiked Amount (µg)	Recovered (µg)	Recovery (%)	Status
Metformin	SS-316	100	92	92%	Pass

Annexure-2: Linearity and Calibration Data

Concentration (µg/mL)	Peak Area	Mean	% RSD
1.0	12000	11985	1.2
2.5	29800	29780	0.9
5.0	61000	60950	1.1

Annexure-3: HPLC Method Validation Report

HPLC method for detection of Metformin on cleaned equipment surfaces was validated successfully. Recovery was 92%, precision RSD 4.2%, and LOD/LOQ were 0.15 µg/mL and 0.45 µg/mL, respectively. Method approved for GMP cleaning validation.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
21/05/2025	2.0	Included MACO calculation and updated acceptance criteria	Annual Review and Regulatory Alignment	Sunita Reddy
05/04/2022	1.0	Initial SOP Release	New SOP	QA Head