Standard Operating Procedure for Limit Test for Chloride and Sulfates in Elixir Formulations
| Department | Elixir Department |
|---|---|
| SOP No. | SOP/ELX/223/2025 |
| Supersedes | SOP/ELX/223/2022 |
| Page No. | Page 1 of 7 |
| Issue Date | 11/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 11/04/2026 |
1. Purpose
To establish a standard procedure for conducting the limit test for chloride and sulfates in elixir formulations using visual comparison against standard solutions as per pharmacopeial guidelines.
2. Scope
This SOP is applicable to the Quality Control Department for testing the presence and permissible levels of chloride and sulfate impurities in raw materials and finished elixir products.
3. Responsibilities
- QC Analyst:
- Carry out the test, prepare reagents, and record observations.
- QC Supervisor:
- Ensure use of appropriate glassware and calibrated instruments.
- QA Officer:
- Review and approve test results before batch release.
4. Accountability
The QC Head is accountable for the accurate execution of the limit test. The QA Head is responsible for compliance with regulatory acceptance criteria and product quality assurance.
5. Procedure
5.1 Limit Test for
Chloride
- Reagents: Nitric acid (dilute), silver nitrate solution (0.1N), standard chloride solution (e.g., 0.05845% NaCl equivalent to 0.035% Cl).
- Take 10 mL of the test solution in a Nessler cylinder.
- Add 1 mL of dilute nitric acid followed by 1 mL of silver nitrate solution.
- Mix and allow to stand for 5 minutes in diffused light.
- Simultaneously, prepare a standard solution using the same procedure.
- Compare the opalescence visually. The test passes if the opalescence in the sample is not greater than that of the standard.
5.2 Limit Test for Sulfates
- Reagents: Hydrochloric acid (dilute), barium chloride solution, standard sulfate solution (e.g., 0.181% K2SO4 equivalent to 0.1% SO42-).
- Take 10 mL of the test solution in a Nessler cylinder.
- Add 1 mL of dilute hydrochloric acid and 1 mL of 10% barium chloride solution.
- Stir with a glass rod and allow to stand for 10 minutes.
- Prepare a standard sulfate solution similarly.
- Compare turbidity. The test passes if the turbidity in the test sample is not more intense than that of the standard.
5.3 Notes
- All glassware must be scrupulously clean and free from contaminants.
- Do not perform the test under direct sunlight or harsh lighting.
- If color interferes, decolorize using activated charcoal (if applicable).
5.4 Acceptance Criteria
- Chloride: Not more than 0.035% w/v (or as per specification).
- Sulfates: Not more than 0.1% w/v (or as per specification).
5.5 Documentation
- Record observations in the Chloride and Sulfate Limit Test Logbook (Annexure-1).
- Attach reagent preparation records and standard preparation references in the batch file.
6. Abbreviations
- SOP: Standard Operating Procedure
- QC: Quality Control
- QA: Quality Assurance
- w/v: Weight per Volume
7. Documents
- Chloride and Sulfate Limit Test Logbook (Annexure-1)
- Glassware and Reagent Preparation Records
- Batch Manufacturing Record (BMR)
8. References
- USP General Chapter <221> – Inorganic Impurities: Tests for Chloride and Sulfate
- IP / BP / Ph. Eur. Monographs for Limit Tests
- 21 CFR Part 211.160 – 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: Chloride and Sulfate Limit Test Logbook
| Date | Batch No. | Chloride Result | Sulfate Result | Pass/Fail | Tested By | Verified By |
|---|---|---|---|---|---|---|
| 11/04/2025 | ELX-0425-041 | Pass | Pass | Pass | 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 Creation | QA Head |
| 11/04/2025 | 2.0 | Revised reagent quantities and test time | Regulatory Alignment | QA Head |