Standard Operating Procedure for Weight per mL Testing During Elixir Manufacturing
| Department | Elixir Department |
|---|---|
| SOP No. | SOP/ELX/205/2025 |
| Supersedes | SOP/ELX/205/2022 |
| Page No. | Page 1 of 8 |
| Issue Date | 11/04/2025 |
| Effective Date | 15/04/2025 |
| Review Date | 11/04/2026 |
1. Purpose
To lay down the procedure for performing and documenting weight per mL testing (also referred to as density or specific gravity testing) of elixir formulations during manufacturing, ensuring consistency in batch quality and regulatory compliance.
2. Scope
This SOP applies to all in-process and finished product weight per mL testing conducted on elixir batches in the Elixir Department. The procedure covers testing at key stages including post-blending and post-final volume adjustment.
3. Responsibilities
- Production Operator:
- Assist in providing the sample to QC and record batch-related data in the BMR.
- QC Analyst:
- Perform weight per mL testing as per method and document the results.
- Ensure balances are calibrated and environmental conditions are suitable.
- QA Officer:
- Verify results and ensure compliance with specified limits.
4. Accountability
The QC Head is accountable for method accuracy and reporting. The Production Head ensures sample integrity. The QA Head
is accountable for batch approval based on accurate testing data.
5. Procedure
5.1 Sample Collection
- Collect approximately 50 mL of sample from the bulk elixir tank after final mixing and before filtration/filling.
- Use a clean, dry, and pre-labeled glass or PET container with tamper-proof seal.
- Label the sample with batch number, date, sampling point, and time.
5.2 Weight per mL Testing
- Use a calibrated pycnometer, density bottle, or a 10 mL calibrated volumetric pipette and analytical balance.
- Calibrate the balance before use as per SOP/QC/BAL/001.
- Procedure:
- Weigh the empty, clean, and dry container (W1).
- Fill exactly 1.0 mL of elixir using a calibrated pipette.
- Weigh the filled container (W2).
- Calculate weight per mL = W2 – W1 (in g/mL).
- Repeat the test in triplicate and calculate the average value.
5.3 Acceptance Criteria
- As per product specification listed in BMR or COA.
- Typical range: ±1.5% of theoretical density.
- In case of out-of-specification results, notify QA immediately and hold the batch for investigation.
5.4 Precautions
- Ensure no air bubbles during pipetting.
- Do not expose sample to light or heat before testing.
- Clean and dry equipment thoroughly between replicates.
5.5 Documentation
- Record all values in the Weight per mL Testing Logbook (Annexure-1).
- Attach balance calibration certificate and pipette calibration record.
- Include results and calculations in the BMR for QA review.
6. Abbreviations
- SOP: Standard Operating Procedure
- QA: Quality Assurance
- QC: Quality Control
- BMR: Batch Manufacturing Record
- COA: Certificate of Analysis
7. Documents
- Weight per mL Testing Logbook (Annexure-1)
- Balance Calibration Record
- Batch Manufacturing Record (BMR)
8. References
- IP/USP/BP General Chapter – Specific Gravity / Density
- 21 CFR Part 211.160 – Laboratory Controls
- WHO TRS 986 – Good Manufacturing Practices
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | |||
| Department |
11. Annexures
Annexure-1: Weight per mL Testing Logbook
| Date | Batch No. | W1 (g) | W2 (g) | Weight/mL (g/mL) | Average | Result | Tested By | QA Verified |
|---|---|---|---|---|---|---|---|---|
| 11/04/2025 | ELX-0425-024 | 12.500 | 13.780 | 1.280 | 1.279 | 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 | Clarified procedure for using volumetric pipette method | Method Enhancement | QA Head |