SOP Guide for Pharma

API Manufacturing: SOP for Polymorph Screening Method – V 2.0

API Manufacturing: SOP for Polymorph Screening Method – V 2.0

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

    1. Select a panel of solvents based on polarity (e.g., water, methanol, acetone, toluene, ethyl acetate, hexane).
    2. Include binary/ternary solvent mixtures to expand screening coverage.
    3. Study cooling, evaporation, and slurry equilibration as crystallization techniques.

    5.2 Experimental Execution

    1. Prepare saturated or near-saturated solutions of the API in selected solvents.
    2. Initiate crystallization using:
      • Cooling (e.g., from 60°C to 5°C)
      • Evaporation (at ambient or reduced pressure)
      • Slurry equilibration (for conversion studies)
    3. Maintain each experiment for a minimum of 24–72 hours for complete crystallization or transformation.
    4. Collect solid samples, filter, and dry at controlled temperature (e.g., 40°C for 6 hours).

    5.3 Analytical Evaluation

    1. 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)
    2. Compare all results with reference standards or previously established polymorphic forms.

    5.4 Documentation and Interpretation

    1. Document all data in “Polymorph Screening Summary Log” (Annexure-1).
    2. Summarize key findings in a “Polymorph Screening Report” including:
      • Polymorph form(s) obtained
      • Stability observation (if tested)
      • Preferred crystallization conditions
    3. 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

    1. Polymorph Screening Summary Log (Annexure-1)
    2. Polymorph Screening Report
    3. 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
    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
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