Standard Operating Procedure for End Point Determination in Granulation via NIR in Analytical Method Development
| Department | Analytical Method Development |
|---|---|
| SOP No. | SOP/AMD/307/2025 |
| Supersedes | SOP/AMD/307/2022 |
| Page No. | Page 1 of 13 |
| Issue Date | 01/06/2025 |
| Effective Date | 03/06/2025 |
| Review Date | 01/06/2026 |
1. Purpose
This SOP defines the procedure for determining the end point of wet granulation using Near Infrared Spectroscopy (NIR).
The goal is to identify the optimal moisture level and ensure batch-to-batch granule consistency by integrating real-time PAT tools into process control decisions.
2. Scope
This SOP is applicable to all wet granulation processes performed within the manufacturing development and analytical labs where NIR is employed as a Process Analytical Technology (PAT) tool to monitor and determine granulation end point in real-time.
3. Responsibilities
- Process Analyst: Prepares and calibrates NIR instrument, collects spectra, and analyzes granulation profile.
- Formulation Scientist: Coordinates granulation run and provides granule samples for model calibration.
- QA Representative: Ensures calibration model validation and maintains data integrity.
- Instrumentation Engineer: Maintains NIR hardware/software and resolves integration issues.
4. Accountability
The Head of Analytical Method Development is accountable for ensuring all granulation end point determination using NIR is validated, repeatable, and documented as per ICH Q8/Q9 and GMP guidelines.
5. Procedure
5.1 NIR Instrument Calibration
- Ensure NIR spectrometer is qualified and installed as per IQ/OQ/PQ protocols.
- Calibrate wavelength accuracy using certified polystyrene film standard.
- Perform photometric and baseline checks using internal diagnostics.
5.2 Reference Method and Sampling
- Use loss on drying (LOD) or Karl Fischer method to generate reference moisture values of granules during development runs.
- Collect granule samples at 2–3 minute intervals during granulation from different process batches.
- Immediately scan each sample using NIR and record the spectra.
5.3 Calibration Model Development
- Import NIR spectra and corresponding moisture content into chemometric software (e.g., SIMCA, Unscrambler, or TQ Analyst).
- Use Partial Least Squares Regression (PLSR) or Principal Component Regression (PCR) for model generation.
- Evaluate model with:
- Correlation Coefficient (R² > 0.98)
- Root Mean Square Error of Calibration (RMSEC)
- Residual Predictive Deviation (RPD > 2.5)
- Validate model with independent dataset (RMSEP ≤ 1%).
5.4 Real-Time Granulation Monitoring
- Position fiber-optic probe in granulator at standardized sampling position.
- Start granulation and initiate real-time spectral acquisition (1 scan every 30 seconds).
- Monitor spectral peak shifts and scores plot against calibration model in real-time.
- Determine end point when:
- Moisture content reaches pre-defined threshold (e.g., 1.5% – 2.5%)
- No further significant changes in absorbance spectra for three consecutive scans
5.5 Data Interpretation and Reporting
- Generate granulation moisture trend graph and overlay batch spectra.
- Document end point decision time, total granulation duration, and final moisture value in Annexure-2.
- Submit report to QA for verification and process record archival.
5.6 Deviation Management
- If end point not achieved or batch exceeds moisture limit, escalate to deviation log.
- Document deviation root cause, corrective measures, and impacted batch disposition.
6. Abbreviations
- NIR: Near Infrared Spectroscopy
- PLSR: Partial Least Squares Regression
- PAT: Process Analytical Technology
- RMSEC: Root Mean Square Error of Calibration
- RMSEP: Root Mean Square Error of Prediction
7. Documents
- Calibration Model Summary – Annexure-1
- Granulation Run Report – Annexure-2
- Deviation Investigation Form – Annexure-3
8. References
- ICH Q8 (R2): Pharmaceutical Development
- ICH Q9: Quality Risk Management
- FDA PAT Guidance: Process Analytical Technology
- 21 CFR Part 11 – Electronic Records and Signatures
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | Ashok Rao | Neha Bhatia | Dr. Harshita Goyal |
| Designation | NIR Analyst | QA Reviewer | Head – AMD |
| Department | Analytical Method Development | Quality Assurance | Analytical Method Development |
11. Annexures
Annexure-1: Calibration Model Summary
| Model ID | Method | R² | RMSEC | RMSEP | Status |
|---|---|---|---|---|---|
| NIR-GR-01 | PLSR Moisture | 0.987 | 0.42 | 0.48 | Approved |
Annexure-2: Granulation Run Report
| Batch No. | Start Time | End Point Time | Moisture (%) | Duration (min) |
|---|---|---|---|---|
| GR-B2301 | 10:00 AM | 10:18 AM | 2.2% | 18 |
Annexure-3: Deviation Investigation Form
| Deviation ID | Description | Root Cause | CAPA | Status |
|---|---|---|---|---|
| DEV-307-01 | End point missed, excess moisture | Probe misalignment | Calibrate probe and retrain operator | Closed |
Revision History:
| Revision Date | Revision No. | Details | Reason | Approved By |
|---|---|---|---|---|
| 01/06/2025 | 2.0 | Expanded NIR probe placement and chemometric model criteria | Annual Review | Dr. Harshita Goyal |
| 20/05/2022 | 1.0 | Initial Release | New SOP | QA Head |