Elixir Department: SOP for Weight per mL Testing – V 2.0

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