Standard Operating Procedure for Preparation and Storage of Working Standards in API Manufacturing
| Department | API Manufacturing |
|---|---|
| SOP No. | SOP/API/132/2025 |
| Supersedes | SOP/API/132/2022 |
| Page No. | Page 1 of 8 |
| Issue Date | 13/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 13/04/2026 |
1. Purpose
To lay down a uniform procedure for the preparation, labeling, qualification, usage, and storage of working standards derived from primary/reference standards used in the analytical testing of Active Pharmaceutical Ingredients (APIs).
2. Scope
This SOP applies to all working standards prepared in the Quality Control laboratory for analytical testing in API manufacturing. It includes both in-house and pharmacopeial reference-based working standards.
3. Responsibilities
- QC Analyst: Prepare and qualify working standards using approved procedures.
- QC Supervisor: Review and approve working standard preparation records.
- QA Officer: Ensure traceability, proper labeling, and expiry management.
4. Accountability
The Head – Quality Control is accountable for the preparation, storage, verification, and documentation of all working standards used in analytical operations.
5. Procedure
5.1 Preparation of Working Standards
- Obtain a qualified reference standard with valid CoA and expiry date.
- Weigh an accurately known amount (e.g., 100 mg) of reference standard using a calibrated balance.
- Dilute with a suitable solvent or buffer to a known concentration (e.g., 1000 µg/mL) using volumetric glassware.
- Label the working standard solution with:
- Working Standard Code (e.g., WS-API-001)
- API name
- Concentration
- Date of preparation
- Prepared by
- Expiry date
5.2 Qualification
- Compare the working standard with the reference standard using appropriate tests:
- Assay by HPLC/UV
- Identity by IR, TLC, or other validated techniques
- Calculate the correction factor or purity value if applicable.
- Record results in the Working Standard Qualification Report (Annexure-1).
- Approve the standard for routine use only if all results are within acceptable criteria.
5.3 Storage Conditions
- Store solid working standards in amber-colored, airtight containers with desiccant.
- Store solution standards in amber-colored vials at recommended conditions (e.g., 2–8°C or as defined in STP).
- Do not use beyond the assigned expiry date or if discoloration/precipitation is observed.
5.4 Usage and Expiry
- Use working standards only for the analysis for which they are qualified.
- Assign a validity of ≤ 6 months from the date of preparation unless otherwise justified.
- Document each use in the Working Standard Usage Log (Annexure-2).
5.5 Disposal
- Discard expired or disqualified working standards following the SOP for chemical waste disposal.
- Record disposal details in the Working Standard Destruction Log (Annexure-3).
6. Abbreviations
- API: Active Pharmaceutical Ingredient
- WS: Working Standard
- QC: Quality Control
- QA: Quality Assurance
- HPLC: High Performance Liquid Chromatography
- IR: Infrared Spectroscopy
7. Documents
- Working Standard Qualification Report (Annexure-1)
- Working Standard Usage Log (Annexure-2)
- Working Standard Destruction Log (Annexure-3)
- STP and Reference Standard CoA
8. References
- ICH Q7 – Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients
- 21 CFR Part 211 – US FDA cGMP Guidelines
- Pharmacopoeial Monographs (USP, BP, IP)
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Working Standard Qualification Report
| Date | WS Code | API Name | Reference Std | Assay (%) | Test Performed | Qualified |
|---|---|---|---|---|---|---|
| 13/04/2025 | WS-API-002 | Metronidazole | RS-API-005 | 99.3% | HPLC/IR | Yes |
Annexure-2: Working Standard Usage Log
| Date | WS Code | Batch No. | Test Type | Used By | Remarks |
|---|---|---|---|---|---|
| 14/04/2025 | WS-API-002 | API-20250413 | Assay | Sunita Reddy | Used within expiry |
Annexure-3: Working Standard Destruction Log
| Date | WS Code | Reason | Quantity Discarded | Disposed By | Verified By |
|---|---|---|---|---|---|
| 15/04/2025 | WS-API-001 | Expired | 150 mg | Ravi Kumar | Rajesh Sharma |
Revision History:
| Revision Date | Revision No. | Details | Reason | Approved By |
|---|---|---|---|---|
| 01/01/2022 | 1.0 | Initial SOP | GMP Compliance | QA Head |
| 13/04/2025 | 2.0 | Added usage logs and destruction documentation | Audit Requirement | QA Head |