Standard Operating Procedure for Viscosity Comparison Between Batches of Elixir Formulations

Department	Elixir Department
SOP No.	SOP/ELX/226/2025
Supersedes	SOP/ELX/226/2022
Page No.	Page 1 of 8
Issue Date	11/04/2025
Effective Date	15/04/2025
Review Date	11/04/2026

1. Purpose

To describe a standardized method for measuring and comparing the viscosity of elixir formulations between production batches using a Brookfield viscometer or equivalent instrument to ensure consistency and product quality.

2. Scope

This SOP applies to the Quality Control Department for in-process and final product testing of viscosity in all batches of elixir formulations. It also supports trend analysis and investigation of process variability.

3. Responsibilities

• QC Analyst:
  • Perform viscosity measurements and record data as per test method.
• QC Supervisor:
  • Review results, verify consistency between batches, and identify outliers.
• QA Officer:
  • Ensure that batch release is aligned with viscosity specifications.

4. Accountability

The QC Head is accountable for conducting viscosity testing as per the defined method. The QA Head is responsible for monitoring batch consistency and approving product release based on viscosity results.

5. Procedure

5.1 Equipment and Materials

• Brookfield viscometer with appropriate spindle set (e.g., LV series)
• Beakers (100 mL/250 mL)
• Thermometer (calibrated)
• Water bath (to maintain sample at 25°C ± 0.5°C)

5.2 Sample Preparation

1. Withdraw approximately 100 mL of the elixir sample.
2. Bring the sample to 25°C using a calibrated water bath.
3. Mix gently to ensure uniformity without introducing air bubbles.

5.3 Instrument Setup

1. Ensure the viscometer is calibrated and on a vibration-free surface.
2. Select the appropriate spindle (e.g., spindle #1 or #2) based on expected viscosity range.
3. Set the rotation speed as per method validation (e.g., 30 rpm).

5.4 Viscosity Measurement

1. Immerse the spindle into the sample to the immersion mark.
2. Start the viscometer and allow reading to stabilize for 30–60 seconds.
3. Record the viscosity in centipoise (cP).
4. Repeat the measurement in triplicate and calculate the average.

5.5 Batch Comparison

1. Compare current batch viscosity with previous 3–5 consecutive batches.
2. If variation is more than ±10% of historical average, investigate for root cause (e.g., ingredient concentration, temperature fluctuation, process deviation).

5.6 Acceptance Criteria

1. Viscosity should be within specified range for the formulation (e.g., 300–600 cP).
2. Trend should remain consistent with previous batches unless justified.

5.7 Documentation

1. Enter results in the Viscosity Comparison Logbook (Annexure-1).
2. Attach instrument printouts or screenshots (if applicable).
3. Include observations in the Batch Manufacturing Record (BMR).

6. Abbreviations

• SOP: Standard Operating Procedure
• QC: Quality Control
• QA: Quality Assurance
• cP: Centipoise
• BMR: Batch Manufacturing Record

7. Documents

1. Viscosity Comparison Logbook (Annexure-1)
2. Instrument Calibration Log
3. Batch Manufacturing Record (BMR)

8. References

• USP General Chapter <911> – Viscosity
• Ph. Eur. 2.2.10 – Viscosity – Capillary Method
• 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: Viscosity Comparison Logbook

Date	Batch No.	Spindle/Speed	Measured Viscosity (cP)	Average of Previous Batches (cP)	Pass/Fail	Tested By	Verified By
11/04/2025	ELX-0425-044	#2/30 rpm	525	510	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	Included batch comparison criteria	Process Monitoring Improvement	QA Head