Standard Operating Procedure for Heavy Metal Testing in Elixir Formulations
| Department | Elixir Department |
|---|---|
| SOP No. | SOP/ELX/222/2025 |
| Supersedes | SOP/ELX/222/2022 |
| Page No. | Page 1 of 9 |
| Issue Date | 11/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 11/04/2026 |
1. Purpose
To define the procedure for the qualitative and/or quantitative testing of heavy metals in elixir formulations using validated analytical methods such as ICP-MS, AAS, or colorimetric methods, in accordance with pharmacopeial and regulatory requirements.
2. Scope
This SOP applies to finished elixir products that are tested for the presence of heavy metals including, but not limited to, lead (Pb), arsenic (As), mercury (Hg), and cadmium (Cd) as part of batch release and stability studies.
3. Responsibilities
- QC Analyst:
- Prepare samples and standards, conduct testing, and record results.
- QC Supervisor:
- Verify test methods, calibration status, and ensure result accuracy.
- QA Officer:
- Review and approve final reports, investigate OOS results if required.
4. Accountability
The QC Head is accountable for the execution and review of heavy metal testing procedures. The QA Head is responsible for ensuring regulatory compliance and batch release decisions based on test outcomes.
5. Procedure
5.1 Sample Preparation
- Take an appropriate quantity of the elixir sample (as per method SOP, typically 10–20 mL).
- Digest the sample using wet digestion method with nitric acid and hydrogen peroxide under a fume hood.
- Filter and dilute the digest to a known volume with deionized water before analysis.
5.2 Standard Preparation
- Prepare calibration standards for lead, arsenic, mercury, and cadmium at known concentrations as per validation protocol.
- Include a blank and quality control standards in each analytical run.
5.3 Instrumental Parameters (ICP-MS/AAS)
- ICP-MS: Preferred for trace level detection; sensitivity up to ppt.
- AAS: Use graphite furnace or hydride generation as per analyte requirement.
- Ensure instruments are calibrated and performance-verified before use.
5.4 Colorimetric Method (Optional)
- Follow USP <231> or other validated method for total heavy metal estimation (as Pb).
- Compare color intensity with lead reference standard after reaction with sodium sulfide or dithizone reagent.
5.5 Acceptance Criteria
- Heavy metal content should comply with product specification:
- Lead (Pb): NMT 0.5 ppm
- Arsenic (As): NMT 1.5 ppm
- Mercury (Hg): NMT 0.1 ppm
- Cadmium (Cd): NMT 0.2 ppm
- For total heavy metals (as Pb), NMT 10 ppm unless otherwise justified.
5.6 Documentation
- Record all data in the Heavy Metal Testing Logbook (Annexure-1).
- Attach chromatograms, calibration curves, and raw data to the batch file.
- Cross-verify results with QA before batch release.
6. Abbreviations
- ICP-MS: Inductively Coupled Plasma Mass Spectrometry
- AAS: Atomic Absorption Spectroscopy
- SOP: Standard Operating Procedure
- QC: Quality Control
- QA: Quality Assurance
- ppm: Parts Per Million
7. Documents
- Heavy Metal Testing Logbook (Annexure-1)
- Instrument Calibration Records
- Batch Manufacturing Record (BMR)
8. References
- USP Chapter <233> – Elemental Impurities
- ICH Q3D – Guideline for Elemental Impurities
- 21 CFR Part 211.165 – Testing and Release for Distribution
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Heavy Metal Testing Logbook
| Date | Batch No. | Pb (ppm) | As (ppm) | Hg (ppm) | Cd (ppm) | Method | Tested By | Verified By |
|---|---|---|---|---|---|---|---|---|
| 11/04/2025 | ELX-0425-040 | 0.3 | 0.8 | <0.05 | 0.1 | ICP-MS | Rajesh Kumar | Sunita Reddy |
Revision History:
| Revision Date | Revision No. | Revision Details | Reason for Revision | Approved By |
|---|---|---|---|---|
| 01/01/2024 | 1.0 | Initial SOP Release | New SOP | QA Head |
| 11/04/2025 | 2.0 | Inclusion of ICP-MS and updated limits per ICH Q3D | Regulatory Alignment | QA Head |