and finished pharmaceutical products, particularly where gas chromatography (GC) is unsuitable due to volatility or matrix interferences.

2. Scope

This procedure applies to the Analytical Method Development (AMD) laboratory and is used to quantify Class 2 and Class 3 solvents (e.g., isopropyl alcohol, ethanol, acetone) in samples using a validated HPLC approach, in alignment with ICH Q3C limits and GMP guidelines.

3. Responsibilities

• Analytical Chemist: Develops and validates the HPLC method, prepares standard and sample solutions, and ensures proper documentation.
• Method Reviewer: Ensures accuracy and regulatory compliance of the developed method.
• QA Officer: Verifies GMP-compliant documentation and cross-verifies validation output.
• Head – AMD: Reviews and approves method for use in quality control or regulatory submission.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring residual solvent methods meet ICH and pharmacopoeial standards for detection and quantification.

5. Procedure

5.1 Selection of Residual Solvents

1. Identify residual solvents from manufacturing or formulation history.
2. Refer to ICH Q3C (R8) for classification and limits:
   • Class 2 (e.g., methanol, acetone): 3000–5000 ppm
   • Class 3 (e.g., ethanol, IPA): 5000 ppm
3. Document selected solvents in Annexure-1: Residual Solvent Selection Sheet.

5.2 Chromatographic Condition Selection

1. Column: C18, 250 mm × 4.6 mm, 5 µm.
2. Mobile Phase:
   • Water:methanol or Water:acetonitrile in 70:30 or 60:40 ratio.
   • Additives (e.g., 0.1% phosphoric acid) to improve separation.
3. Detection: UV at 210–220 nm depending on solvent absorbance.
4. Flow Rate: 1.0 mL/min; Injection Volume: 50 µL (larger than typical assay injections).
5. Record settings in Annexure-2: HPLC Conditions Log.

5.3 Standard and Sample Preparation

1. Standard Preparation:
   • Prepare individual and mixed standard stock solutions of solvents in water or diluent.
   • Dilute to concentrations near ICH limits (e.g., 2000–5000 ppm).
2. Sample Preparation:
   • Weigh API or formulation (e.g., 500 mg) into 10 mL volumetric flask.
   • Extract with diluent using sonication, then dilute and filter.
3. Document all weights and dilutions in Annexure-3: Sample & Standard Preparation Log.

5.4 Specificity and Linearity

1. Inject blank, standard, and sample to verify no interference at solvent RTs.
2. Prepare linearity curve for each solvent (50%, 75%, 100%, 125%, 150%).
3. Acceptance criteria: R² ≥ 0.995.
4. Document results in Annexure-4: Linearity and Specificity Report.

5.5 Accuracy and Precision

1. Accuracy:
   • Spike blank matrix (API without solvents) at 80%, 100%, and 120% levels.
   • Recovery range: 95–105%
2. Precision:
   • Repeat injection of standard solution (n=6); %RSD ≤ 5%
3. Document in Annexure-5: Accuracy and Precision Log.

5.6 Limit of Detection (LOD) and Limit of Quantification (LOQ)

1. Determine LOD and LOQ based on signal-to-noise (S/N) method:
   • LOD: S/N ≥ 3
   • LOQ: S/N ≥ 10
2. Confirm %RSD at LOQ is ≤10%.
3. Record in Annexure-6: LOD/LOQ Summary.

5.7 Robustness and System Suitability

1. Change flow rate ±0.1 mL/min, pH ±0.2, or detection wavelength ±2 nm.
2. Evaluate impact on retention time and resolution.
3. System Suitability Criteria:
   • RSD of solvent peak areas ≤ 5%
   • Resolution between solvents ≥ 2.0
4. Document in Annexure-7: Robustness and Suitability Report.

6. Abbreviations

• HPLC: High-Performance Liquid Chromatography
• LOD: Limit of Detection
• LOQ: Limit of Quantification
• ICH: International Council for Harmonisation
• RSD: Relative Standard Deviation
• SOP: Standard Operating Procedure

7. Documents

1. Residual Solvent Selection Sheet – Annexure-1
2. HPLC Conditions Log – Annexure-2
3. Sample & Standard Preparation Log – Annexure-3
4. Linearity and Specificity Report – Annexure-4
5. Accuracy and Precision Log – Annexure-5
6. LOD/LOQ Summary – Annexure-6
7. Robustness and Suitability Report – Annexure-7

8. References

• ICH Q3C(R8) – Impurities: Guideline for Residual Solvents
• ICH Q2(R1) – Validation of Analytical Procedures
• USP <467> – Residual Solvents
• USP <621> – Chromatography

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Residual Solvent Selection Sheet

Solvent	Class	ICH Limit (ppm)	Included in Method
Isopropyl Alcohol	Class 3	5000	Yes

Annexure-2: HPLC Conditions Log

Column	Mobile Phase	Flow Rate	Wavelength	Run Time
C18, 250×4.6 mm	Water:Methanol (70:30)	1.0 mL/min	210 nm	15 min

Annexure-3: Sample & Standard Preparation Log

ID	Type	Concentration	Diluent	Prepared By
STD-001	IPA Standard	4000 ppm	Water	Rajesh Kumar

Annexure-4: Linearity and Specificity Report

Level	Concentration (ppm)	Area	R²
100%	4000	265432	0.9996

Annexure-5: Accuracy and Precision Log

Level	Recovery (%)	RSD (%)	Status
100%	99.2	1.4	Pass

Annexure-6: LOD/LOQ Summary

Solvent	LOD (ppm)	LOQ (ppm)	S/N @ LOQ
IPA	80	260	11

Annexure-7: Robustness and Suitability Report

Parameter	Variation	Observation	Status
Flow Rate	±0.1 mL/min	RT shift < 0.5 min	Acceptable

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Added larger injection volume guidance and LOD/LOQ criteria	Annual SOP Update