products in accordance with ICH Q3C and applicable pharmacopeial standards.

2. Scope

This procedure applies to the Analytical Method Development (AMD) team responsible for the analysis of volatile organic compounds (VOCs) using HS-GC in APIs and formulated drug products.

3. Responsibilities

• Analytical Scientist: Designs and performs HS-GC method development and validation experiments.
• Instrument Analyst: Operates the headspace autosampler and GC system, ensures calibration and maintenance.
• QA Officer: Reviews validation reports and ensures documentation complies with GMP and ICH requirements.
• Head – AMD: Approves method development plans and validation reports.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring that all headspace GC methods for residual solvent analysis are scientifically valid, accurate, and regulatory compliant.

5. Procedure

5.1 Selection of Target Solvents

1. Identify solvents used in manufacturing from batch records.
2. Classify per ICH Q3C: Class 1 (to be avoided), Class 2 (limited), Class 3 (low toxic potential).
3. Set acceptance limits based on permitted daily exposure (PDE).

5.2 Sample Preparation

1. Weigh 500–1000 mg of sample into a clean headspace vial.
2. Add 5 mL of diluent (e.g., N,N-dimethylformamide (DMF), DMSO, or water).
3. Seal with crimp cap and septum. Vortex for homogeneity.
4. Add internal standard (e.g., 1-butanol) to standard and sample vials.

5.3 Instrument Configuration

1. Headspace Sampler Settings:
   • Oven Temp: 80°C
   • Loop Temp: 90°C
   • Transfer Line: 100°C
   • Equilibration Time: 30 min
2. GC Conditions:
   • Column: DB-624 (30 m × 0.32 mm × 1.8 µm)
   • Carrier Gas: Helium at 1.0 mL/min
   • Detector: FID
   • Injector Temp: 200°C (split mode)
   • Oven Temp Program: Start at 40°C, ramp to 240°C at 10°C/min

5.4 Calibration Curve

1. Prepare calibration solutions at concentrations of 50%, 100%, and 150% of limit.
2. Include internal standard in each level.
3. Plot area ratio (analyte/IS) vs concentration. R² ≥ 0.995 required.
4. Document in Annexure-1: Calibration Curve Log.

5.5 Method Validation

1. Validate the method as per ICH Q2(R2):
   • Specificity – No interference from matrix
   • Linearity – 50% to 150% of specification
   • Accuracy – Recovery between 90%–110%
   • Precision – RSD ≤ 5% for n=6
   • LOD and LOQ determination
2. Document in Annexure-2: Method Validation Report.

5.6 Routine Sample Analysis

1. Run system suitability (e.g., resolution, %RSD of replicate injections).
2. Inject samples and compare results to ICH Q3C limits.
3. Document final result in Annexure-3: Sample Test Log.

6. Abbreviations

• HS-GC: Headspace Gas Chromatography
• FID: Flame Ionization Detector
• LOD: Limit of Detection
• LOQ: Limit of Quantification
• IS: Internal Standard
• SOP: Standard Operating Procedure

7. Documents

1. Calibration Curve Log – Annexure-1
2. Method Validation Report – Annexure-2
3. Sample Test Log – Annexure-3

8. References

• ICH Q3C(R8) – Residual Solvents
• ICH Q2(R2) – Validation of Analytical Procedures
• USP <467> – Residual Solvents by Headspace GC

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Calibration Curve Log

Solvent	Concentration (ppm)	Area Ratio (Analyte/IS)	Analyst
Methanol	300	0.965	Sunita Reddy

Annexure-2: Method Validation Report

Parameter	Result	Acceptance	Status
Linearity	R² = 0.9982	≥ 0.995	Pass
Recovery	96.8%–101.1%	90%–110%	Pass

Annexure-3: Sample Test Log

Sample ID	Solvent	Content (ppm)	Limit	Status
API-BT-107	Acetone	210	≤ 500	Complies

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Integrated system suitability and expanded validation steps	Annual SOP Review