as FTIR, UV, HPLC, and thermal analysis.

2. Scope

This SOP applies to Analytical Method Development and Quality Control departments involved in the qualitative and semi-quantitative analysis of film coatings, enteric coatings, and sustained-release polymers used in tablet or capsule formulations.

3. Responsibilities

• Analytical Scientist: Develops and executes analytical methods for coating material identification.
• QC Analyst: Performs routine analysis and documentation of results.
• QA Executive: Verifies compliance and ensures traceability of results for regulatory submissions.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring that all analytical techniques used for coating identification are validated, reliable, and compliant with ICH and pharmacopeial guidelines.

5. Procedure

5.1 Sample Preparation

1. Gently scrape the coating from 10 tablets or remove coating using suitable solvent (e.g., water, ethanol, or methanol).
2. Dry and weigh the residue if needed for quantitative estimation.
3. Dissolve or disperse the coating material in an appropriate solvent for further analysis.

5.2 FTIR Spectroscopy

1. Prepare a KBr pellet or use ATR mode for film residues.
2. Record spectra from 4000–400 cm^-1.
3. Compare against standard library spectra for common coating materials (e.g., HPMC, PVA, Eudragit®, ethyl cellulose).

5.3 UV-Vis Spectrophotometry

1. Applicable for colored coatings or functional layers with UV-absorbing excipients.
2. Measure λ_max and compare absorbance with standard solutions.

5.4 HPLC Analysis

1. Dissolve coating in methanol or suitable mobile phase.
2. Inject 20 µL onto a C18 column using gradient or isocratic conditions.
3. Detect typical polymers or plasticizers (e.g., PEG, triethyl citrate) based on known retention times.

5.5 Thermal Analysis (DSC/TGA)

• Use Differential Scanning Calorimetry (DSC) or Thermogravimetric Analysis (TGA) to assess thermal properties of film coatings.
• Identify unique endothermic/exothermic transitions or degradation patterns indicative of specific polymers.

5.6 Data Interpretation

• Use overlay comparison against reference materials for confirmation.
• Report matches with confidence score (for FTIR), retention time match (for HPLC), and melting point/Tg (for DSC).

6. Abbreviations

• FTIR: Fourier Transform Infrared Spectroscopy
• HPLC: High Performance Liquid Chromatography
• DSC: Differential Scanning Calorimetry
• Tg: Glass Transition Temperature
• QA: Quality Assurance

7. Documents

1. Coating Identification Data Log – Annexure-1
2. FTIR/HPLC Chromatograms – Annexure-2
3. Thermal Profile Comparison Sheet – Annexure-3

8. References

• USP <831>: Infrared Spectrophotometry
• ICH Q6A: Specifications: Test Procedures and Acceptance Criteria
• Ph. Eur. 2.2.24: Identification by Infrared Spectrophotometry

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Rekha Kulkarni	Anil Chauhan	Sunita Reddy
Designation	Analytical Chemist	QA Reviewer	Head – AMD
Department	Analytical Method Development	QA	Analytical Method Development

11. Annexures

Annexure-1: Coating Identification Data Log

Sample ID	Test Performed	Polymer Identified	Status
CMT-287-01	FTIR	HPMC	Confirmed

Annexure-2: FTIR/HPLC Chromatograms

Overlay of sample spectra with reference polymer. Peak at 1045 cm^-1 confirms HPMC identity.

Annexure-3: Thermal Profile Comparison Sheet

DSC curve shows endothermic transition at 170°C matching reference HPMC polymer.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
21/05/2025	2.0	Included thermal and UV analysis, clarified sample prep for coated tablets	Annual Review	Sunita Reddy
05/10/2022	1.0	Initial SOP Release	New SOP	QA Head