SOP Guide for Pharma

Elixir Department: SOP for Solubility Testing at Intermediate Stages – V 2.0

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Elixir Department: SOP for Solubility Testing at Intermediate Stages – V 2.0

Standard Operating Procedure for Solubility Testing at Intermediate Stages in Elixir Manufacturing

Department Elixir Department
SOP No. SOP/ELX/197/2025
Supersedes SOP/ELX/197/2022
Page No. Page 1 of 8
Issue Date 11/04/2025
Effective Date 15/04/2025
Review Date 11/04/2026

1. Purpose

To define a standardized procedure for performing solubility testing of active ingredients and excipients at intermediate stages of elixir manufacturing to ensure complete dissolution and avoid precipitation during further processing.

2. Scope

This SOP applies to all elixir batches that require confirmation of solubility of active ingredients and selected excipients after their addition during processing, and prior to bulk completion.

3. Responsibilities

  • Production Operator:
    • Collect samples for solubility testing as per stage-wise instructions.
  • QC Analyst:
    • Perform solubility checks using visual inspection, centrifugation, or filtration, and document findings.
  • QA Officer:
    • Ensure compliance with sampling and testing procedures and review results.
See also  Elixir Department: SOP for SIP (Steam in Place) Process - V 2.0

4. Accountability

The Production Head is accountable for correct sampling. QC Head is responsible for test accuracy. QA is accountable for documentation and compliance verification.

5. Procedure

5.1 Sampling

for Solubility Testing
  1. Sample after complete addition and mixing of the API or excipient in the manufacturing tank.
  2. Collect 50 mL of the sample in a clean, dry, transparent glass vial.
  3. Label with product name, batch number, stage, date, and “Solubility Sample.”
  4. Transport the sample to the QC lab immediately to avoid temperature-induced solubility shifts.

5.2 Testing Procedure

  1. Visual Inspection: Hold the vial against white and black backgrounds and observe for undissolved particles, turbidity, or haze.
  2. Filtration Method:
    • Filter 10 mL of the sample through a 0.45 µm filter paper.
    • Check for residue on the filter. No visible residue indicates complete solubility.
  3. Centrifugation Method:
    • Centrifuge 10 mL of the sample at 3000 rpm for 10 minutes.
    • Check for sediment or phase separation.

5.3 Acceptance Criteria

  1. The solution must appear clear or as per product specifications.
  2. No visible undissolved particles, sediments, or phase separation should be observed.
  3. If undissolved matter is present, notify Production and QA for reprocessing or mixing extension.

5.4 Corrective Actions for Non-Conformance

  1. Hold the batch and inform QA.
  2. Repeat mixing and re-test solubility.
  3. If solubility is not achieved after reprocessing, escalate to product development and initiate deviation handling.

5.5 Documentation

  1. Record test results in the Solubility Testing Logbook (Annexure-1).
  2. Include batch details, test method used, observation, interpretation, and analyst initials.
  3. Attach supporting evidence such as filter papers (if applicable) to the batch documentation file.

6. Abbreviations

  • SOP: Standard Operating Procedure
  • QC: Quality Control
  • QA: Quality Assurance
  • API: Active Pharmaceutical Ingredient
  • RPM: Revolutions Per Minute

7. Documents

  1. Solubility Testing Logbook (Annexure-1)
  2. Batch Manufacturing Record (BMR)
  3. Analytical Method Sheet

8. References

  • ICH Q6A – Specifications: Test Procedures and Acceptance Criteria
  • WHO TRS 986 – GMP for Pharmaceuticals
  • 21 CFR Part 211 – Subpart I: Laboratory Controls

9. SOP Version

Version: 2.0

10. Approval Section

Prepared By Checked By Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Solubility Testing Logbook

Date Batch No. Stage Test Method Observation Result Analyst QA Verified
11/04/2025 ELX-0425-016 Post-API Addition Filtration No Residue on Filter Pass Rajesh Kumar Sunita Reddy

Revision History:

Revision Date Revision No. Revision Details Reason for Revision Approved By
01/01/2024 1.0 Initial Release New SOP QA Head
11/04/2025 2.0 Added centrifugation method and corrective action flow Process Enhancement QA Head
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