identity confirmation.

2. Scope

This procedure applies to the Analytical Method Development (AMD) laboratory and covers FTIR spectrum generation of pure APIs, intermediates, and excipients using potassium bromide (KBr) pellet or ATR techniques.

3. Responsibilities

• Analytical Chemist: Prepares the sample and collects the FTIR spectrum.
• Reviewer: Compares spectra with reference standards and interprets functional group regions.
• QA Officer: Verifies documentation for compliance with ICH and pharmacopeial requirements.
• Head – AMD: Reviews and approves final spectral data and interpretation reports.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring the FTIR fingerprint spectrum is scientifically valid and compliant with GMP, ICH Q2(R1), and regulatory expectations for identity confirmation.

5. Procedure

5.1 Instrument Calibration

1. Ensure FTIR spectrometer is qualified and calibrated as per internal procedures.
2. Verify wavelength accuracy using polystyrene film; confirm peaks at ~1601 cm^-1 and ~1154 cm^-1.
3. Document calibration check in Annexure-1: Instrument Calibration Record.

5.2 Sample Preparation

1. KBr Pellet Method:
   • Dry KBr (IR grade) at 105°C for at least 2 hours before use.
   • Grind 1-2 mg of API with ~200 mg KBr in a mortar and pestle until uniform.
   • Compress into a transparent pellet using a hydraulic press.
2. ATR Method (if applicable):
   • Place a small amount of dry API powder directly on the ATR crystal.
   • Apply uniform pressure using the pressure arm for good contact.
3. Document preparation method in Annexure-2: Sample Preparation Log.

5.3 Background Collection

1. Run a background scan using dry KBr pellet or empty ATR crystal.
2. Ensure the background is collected immediately before sample scan to eliminate atmospheric CO₂ and H₂O interference.
3. Record scan parameters in Annexure-3: Background Log.

5.4 Sample Spectrum Collection

1. Collect the spectrum in transmittance mode from 4000 to 400 cm^-1.
2. Set resolution to 4 cm^-1, with 32–64 scans per sample for adequate signal-to-noise ratio.
3. Record absorbance peaks and baseline quality.
4. Save spectrum file and export as PDF or ASCII format.
5. Print spectrum and paste in Annexure-4: Sample Spectrum Record.

5.5 Interpretation of Fingerprint Region

1. Focus on region from 1800 to 600 cm^-1 for fingerprint identification.
2. Compare peak position, shape, and intensity with that of reference standard.
3. Functional group region (4000–1800 cm^-1) may be used to support interpretation.
4. Confirm presence of key peaks such as:
   • C=O: ~1700 cm^-1
   • OH (broad): ~3200–3500 cm^-1
   • CH stretch: ~2800–3000 cm^-1
5. Record interpretation in Annexure-5: Peak Assignment Sheet.

5.6 Comparison with Reference Standard

1. Overlay test and reference spectra using instrument software.
2. Acceptance criteria: spectra should be concordant with reference spectrum with no additional or missing peaks in fingerprint region.
3. Document overlay and conclusion in Annexure-6: Spectrum Comparison Sheet.

5.7 Precautions

1. Ensure all samples and KBr are moisture-free to prevent O-H stretching interference.
2. Clean ATR crystal thoroughly before and after use to prevent cross-contamination.
3. Use desiccators for storing KBr and prepared pellets.

6. Abbreviations

• FTIR: Fourier Transform Infrared Spectroscopy
• ATR: Attenuated Total Reflectance
• API: Active Pharmaceutical Ingredient
• KBr: Potassium Bromide
• SOP: Standard Operating Procedure
• cm^-1: Wavenumber (reciprocal centimeters)

7. Documents

1. Instrument Calibration Record – Annexure-1
2. Sample Preparation Log – Annexure-2
3. Background Log – Annexure-3
4. Sample Spectrum Record – Annexure-4
5. Peak Assignment Sheet – Annexure-5
6. Spectrum Comparison Sheet – Annexure-6

8. References

• ICH Q2(R1) – Validation of Analytical Procedures
• USP <197K> – Infrared Spectrophotometry
• Pharmaceutical Infrared Spectroscopy Texts
• FTIR Instrument Manufacturer’s Manual

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Instrument Calibration Record

Date	Standard Used	Wavelengths Observed (cm-1)	Status
19/05/2025	Polystyrene Film	1601, 1154	Pass

Annexure-2: Sample Preparation Log

Sample ID	Method	KBr Quantity (mg)	API Weight (mg)	Remarks
API-FTIR-096	KBr Pellet	200	1.5	Uniform Mix

Annexure-3: Background Log

Date	Mode	Solvent/KBr Used	Status
19/05/2025	Transmittance	Dry KBr	Clear

Annexure-4: Sample Spectrum Record

Attach printed FTIR spectrum here along with file name, scan parameters, and analyst initials.

Annexure-5: Peak Assignment Sheet

Peak Position (cm-1)	Functional Group	Interpretation
1702	C=O Stretch	Present
2955	CH Stretch	Alkane

Annexure-6: Spectrum Comparison Sheet

Sample	Reference	Overlay Match (%)	Conclusion
API-FTIR-096	Reference-096	98.9%	Match

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Enhanced interpretation section and expanded annexure fields	Annual SOP Review