Standard Operating Procedure for Measuring Specific Gravity of Cream Batches

Department	Creams
SOP No.	SOP/CRM/065/2025
Supersedes	SOP/CRM/065/2022
Page No.	Page 1 of 5
Issue Date	06/01/2026
Effective Date	11/01/2026
Review Date	06/01/2027

1. Purpose

The purpose of this Standard Operating Procedure (SOP) is to outline the procedure for measuring the specific gravity of cream batches. Specific gravity is a key physical property used to assess the density of cream formulations and is essential for ensuring product consistency, quality, and uniformity. This SOP ensures that specific gravity measurements are performed accurately and in compliance with Good Manufacturing Practices (GMP).

2. Scope

This SOP applies to all cream batches manufactured in the Creams Department. It includes the procedure for measuring specific gravity using calibrated instruments, documenting results, and ensuring that the measurements fall within the defined product specifications.

3. Responsibilities

• Production Team: Responsible for taking specific gravity measurements during the manufacturing process, ensuring that the procedure is followed correctly, and documenting results as per this SOP.
• Quality Control (QC): Responsible for verifying the specific gravity measurements, reviewing the data, and ensuring that they meet the required product specifications.
• Quality Assurance (QA): Ensures compliance with this SOP and GMP guidelines, reviewing measurement records and approving the final product batch for release.
• Maintenance Team: Responsible for calibrating and maintaining the instruments used for measuring specific gravity, ensuring their accuracy and reliability.

4. Accountability

The Head of Creams Manufacturing is responsible for ensuring that this SOP is implemented correctly across the production process. The QA Manager is accountable for reviewing the specific gravity measurement records and approving the batch for release based on compliance with the product specifications.

5. Procedure

5.1 Pre-Measurement Preparation

1. Ensure that all required equipment for measuring specific gravity, including a calibrated hydrometer, pycnometer, or density meter, is available and in good working condition.
2. Verify that the measuring instruments have been calibrated according to the manufacturer’s specifications and are within the required tolerance limits.
3. Prepare the cream sample to be tested by ensuring it is well-mixed and homogeneous. If the sample is too thick, it may need to be slightly heated to facilitate measurement.
4. Ensure that the temperature of the cream sample is within the acceptable range (typically between 20°C and 25°C) to avoid temperature-related errors in the measurement.

5.2 Measuring Specific Gravity

1. Select an appropriate measuring instrument (hydrometer, pycnometer, or density meter) based on the batch size and type of cream being processed.
2. If using a hydrometer, gently lower it into the cream sample container, ensuring that the hydrometer is floating freely without any interference from the container walls.
3. Record the reading on the hydrometer scale once it stabilizes. For a pycnometer, fill the device with the cream sample and weigh it accurately, then calculate the specific gravity based on the volume and mass.
4. If using a density meter, follow the manufacturer’s instructions to obtain an accurate specific gravity measurement directly from the instrument’s display.
5. Record the specific gravity measurement in the Specific Gravity Measurement Log (Annexure-1), including the batch number, time of measurement, and operator details.
6. Repeat the measurement at least once to ensure accuracy. If the measurements vary, take additional readings until consistent results are obtained.

5.3 Post-Measurement Procedures

1. Compare the recorded specific gravity against the acceptable range defined in the product specifications. This range is typically determined based on the formulation and desired texture of the cream.
2. If the specific gravity falls outside the acceptable range, investigate potential causes such as incorrect ingredient ratios, improper mixing, or temperature deviations. Record the deviation in the Deviation Report Form (Annexure-2).
3. In case of a deviation, perform corrective actions, which may include adjusting the formula, remixing, or recalculating ingredient quantities, and re-measuring the specific gravity after adjustments.
4. If the specific gravity meets the required specifications, proceed with the next stage of production (e.g., cooling, filling, or packaging).

5.4 Documentation

1. Document all specific gravity measurements in the Specific Gravity Measurement Log (Annexure-1). Include the following details:
   • Batch number
   • Date and time of measurement
   • Instrument used
   • Specific gravity reading
   • Operator’s initials
   • Comments (if applicable)
2. In the event of any deviations, record the details in the Deviation Report Form (Annexure-2) and follow the deviation handling procedure to resolve the issue.
3. Ensure that all records are signed and reviewed by the QA team to ensure compliance with this SOP and product quality standards.

5.5 Equipment Calibration

1. Ensure that all instruments used to measure specific gravity are calibrated at regular intervals according to the manufacturer’s guidelines.
2. Maintain calibration records and verify that the instruments are within the specified tolerance range before each measurement session.
3. If calibration is found to be out of tolerance, send the equipment for recalibration or replace it with a properly calibrated instrument before proceeding with measurements.

5.6 Final Approval

1. The QA team must review the specific gravity measurement records and approve the batch for further processing or release based on compliance with the required specifications.
2. If any corrective actions or deviations occurred, ensure that the corrective actions taken are documented and reviewed by QA.

6. Abbreviations

• QC: Quality Control
• QA: Quality Assurance
• GMP: Good Manufacturing Practices
• PPE: Personal Protective Equipment

7. Documents

1. Specific Gravity Measurement Log (Annexure-1)
2. Deviation Report Form (Annexure-2)

8. References

• Good Manufacturing Practices (GMP) Guidelines – 21 CFR Part 211
• International Conference on Harmonisation (ICH) Q7 – Good Manufacturing Practice for Active Pharmaceutical Ingredients
• FDA Guidelines for Cosmetics Manufacturing

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Specific Gravity Measurement Log

Batch Number	Time of Measurement	Instrument Used	Specific Gravity Reading	Operator	Comments
12345	08:00 AM	Hydrometer	1.02	Jane Smith	No issues

Annexure-2: Deviation Report Form

Deviation Description	Time	Batch Number	Operator	Immediate Action
Specific gravity outside range	08:30 AM	12345	John Doe	Re-mixed batch

Revision History:

Revision Date	Revision No.	Revision Details	Reason for Revision	Approved By
01/03/2024	1.0	Initial Version	New SOP Creation	QA Head
01/03/2025	2.0	Format Revision and Updates	Standardization of Document	QA Head