Scope

This SOP is applicable to the Analytical Method Development (AMD) department for using Raman spectroscopy in routine identification testing, polymorph analysis, counterfeit detection, and process analytical technology (PAT) applications.

3. Responsibilities

• Analytical Scientist: Develops method parameters, interprets spectral data, and validates method performance.
• Instrument Analyst: Operates Raman spectrometer, performs system suitability, and manages raw data.
• QA Officer: Reviews validation reports and ensures GMP compliance.
• Head – AMD: Approves Raman methods and ensures regulatory alignment.

4. Accountability

The Head of Analytical Method Development is accountable for the scientific integrity, regulatory compliance, and approval of Raman spectroscopy methods used within the pharmaceutical facility.

5. Procedure

5.1 Instrument Setup and Calibration

1. Calibrate the Raman spectrometer using certified standards such as polystyrene or silicon wafer (peak at 520.7 cm⁻¹).
2. Check wavenumber accuracy and laser stability.
3. Log calibration data in Annexure-1: Raman Calibration Log.

5.2 Sample Preparation

1. No special preparation required for solids; powders can be analyzed directly.
2. Liquids or gels can be analyzed using vials or immersion probes.
3. Ensure sample is homogeneous and clean from dust or external contamination.

5.3 Method Parameters

1. Excitation Wavelength: 785 nm (preferred), 532 nm or 1064 nm based on fluorescence profile.
2. Laser Power: 10–100 mW, optimize to avoid sample degradation.
3. Acquisition Time: 1–10 seconds per scan.
4. Number of Scans: 3–10 accumulations for noise reduction.
5. Spectral Range: 200–1800 cm⁻¹ typical (adjust based on compound).

5.4 Spectral Acquisition and Interpretation

1. Collect spectra of reference standard, test sample, and blank.
2. Process data using software with baseline correction, smoothing, and normalization.
3. Compare test sample spectrum with library/reference using match score or overlay plots.
4. Document peak positions and intensities in Annexure-2: Raman Spectral Log.

5.5 Method Validation

1. Validate method according to ICH Q2(R2) and regulatory expectations:
   • Specificity: Distinguish target compound from structurally similar substances.
   • Precision: RSD ≤ 2% for peak intensity at key wavenumbers.
   • Accuracy: Compare with orthogonal method (e.g., IR, HPLC).
   • Robustness: Vary laser power and acquisition time.
   • LOD/LOQ: Based on signal-to-noise (S/N) criteria.
2. Summarize findings in Annexure-3: Validation Summary.

5.6 Application Scenarios

1. Polymorph screening during drug development.
2. Raw material verification at warehouse stage.
3. Monitoring blend uniformity in process development.
4. Authentication of genuine vs. counterfeit products.

6. Abbreviations

• Raman: Raman Spectroscopy
• GMP: Good Manufacturing Practice
• RSD: Relative Standard Deviation
• LOD: Limit of Detection
• LOQ: Limit of Quantification
• SOP: Standard Operating Procedure

7. Documents

1. Raman Calibration Log – Annexure-1
2. Raman Spectral Log – Annexure-2
3. Validation Summary – Annexure-3

8. References

• ICH Q2(R2) – Validation of Analytical Procedures
• USP <858> – Raman Spectroscopy
• FDA Guidance on Process Analytical Technology (PAT)

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Raman Calibration Log

Date	Standard Used	Theoretical Peak (cm⁻¹)	Observed Peak (cm⁻¹)	Deviation	Analyst
18/05/2025	Silicon	520.7	520.6	–0.1	Rajesh Kumar

Annexure-2: Raman Spectral Log

Sample ID	Major Peaks (cm⁻¹)	Match Score (%)	Comments	Analyst
RM-API-010	641, 812, 1215	98.7%	Confirmed identity	Sunita Reddy

Annexure-3: Validation Summary

Parameter	Result	Acceptance Criteria	Status
Precision	RSD = 1.3%	≤ 2%	Pass
Specificity	No interference	Distinct spectral peaks	Pass

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Expanded validation parameters and updated application section	Annual SOP Review