Standard Operating Procedure for Polymorph Screening Method in API Manufacturing
Department | API Manufacturing |
---|---|
SOP No. | SOP/API/063/2025 |
Supersedes | SOP/API/063/2022 |
Page No. | Page 1 of 10 |
Issue Date | 13/04/2025 |
Effective Date | 15/04/2025 |
Review Date | 13/04/2026 |
1. Purpose
To establish a standard and scientifically robust procedure for polymorph screening in API development and manufacturing to ensure the identification and control of solid-state forms of active pharmaceutical ingredients.
2. Scope
This SOP applies to all new and existing API compounds undergoing development, scale-up, or process optimization phases, where polymorphic behavior may impact stability, solubility, bioavailability, or regulatory requirements.
3. Responsibilities
- R&D
Scientists: Conduct polymorph screening experiments and interpret analytical data.
QC Department: Perform XRPD, DSC, and microscopy for solid-state characterization.
QA Department: Review reports and support documentation for regulatory submissions.
Technology Transfer Team: Ensure screened polymorph is consistently reproduced in plant batches.
4. Accountability
The R&D Head is accountable for execution and documentation of polymorph screening. The QA Head is responsible for review and archival of polymorph data.
5. Procedure
5.1 Selection of Solvents and Conditions
- Select a panel of solvents based on polarity (e.g., water, methanol, acetone, toluene, ethyl acetate, hexane).
- Include binary/ternary solvent mixtures to expand screening coverage.
- Study cooling, evaporation, and slurry equilibration as crystallization techniques.
5.2 Experimental Execution
- Prepare saturated or near-saturated solutions of the API in selected solvents.
- Initiate crystallization using:
- Cooling (e.g., from 60°C to 5°C)
- Evaporation (at ambient or reduced pressure)
- Slurry equilibration (for conversion studies)
- Maintain each experiment for a minimum of 24–72 hours for complete crystallization or transformation.
- Collect solid samples, filter, and dry at controlled temperature (e.g., 40°C for 6 hours).
5.3 Analytical Evaluation
- Perform the following analyses:
- XRPD: X-ray Powder Diffraction for crystal form identification
- DSC: Differential Scanning Calorimetry for melting behavior
- TGA: Thermogravimetric Analysis if solvates/hydrates are expected
- Microscopy: Crystal morphology under polarizing microscope
- FTIR: To detect conformational polymorphs (if applicable)
- Compare all results with reference standards or previously established polymorphic forms.
5.4 Documentation and Interpretation
- Document all data in “Polymorph Screening Summary Log” (Annexure-1).
- Summarize key findings in a “Polymorph Screening Report” including:
- Polymorph form(s) obtained
- Stability observation (if tested)
- Preferred crystallization conditions
- Route the selected polymorph and its control strategy into process development.
6. Abbreviations
- XRPD: X-Ray Powder Diffraction
- DSC: Differential Scanning Calorimetry
- TGA: Thermogravimetric Analysis
- SOP: Standard Operating Procedure
- API: Active Pharmaceutical Ingredient
- QC: Quality Control
- QA: Quality Assurance
7. Documents
- Polymorph Screening Summary Log (Annexure-1)
- Polymorph Screening Report
- Analytical Raw Data (XRPD, DSC, etc.)
8. References
- ICH Q6A – Specifications: Test Procedures and Acceptance Criteria for New Drug Substances and Products
- FDA Guidance on ANDAs: Pharmaceutical Solid Polymorphism
- Internal Polymorph Study Guidelines
9. SOP Version
Version: 2.0
10. Approval Section
Prepared By | Checked By | Approved By | |
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Signature | |||
Date | |||
Name | |||
Designation | |||
Department |
11. Annexures
Annexure-1: Polymorph Screening Summary Log
Date | API Name | Solvent | Method | Polymorph Observed | Remarks |
---|---|---|---|---|---|
13/04/2025 | API-A | Acetone | Cooling | Form I | Matched with Reference |
Revision History:
Revision Date | Revision No. | Details | Reason | Approved By |
---|---|---|---|---|
01/01/2022 | 1.0 | Initial SOP Release | New Polymorph Control Program | QA Head |
13/04/2025 | 2.0 | Added Binary Solvent System Screening | Project Expansion | QA Head |