with internal specifications and regulatory requirements.

4. Accountability

The QC Manager is accountable for ensuring that water activity testing is conducted accurately and in accordance with this SOP. The Production Supervisor is responsible for ensuring that samples are collected and handled properly. The QA Manager ensures that the water activity results are reviewed and approved in compliance with GMP and regulatory standards.

5. Procedure

5.1 Pre-Test Preparation

1. Ensure that all necessary equipment for water activity measurement is available, including a calibrated water activity meter, sample containers, and any required reagents.
2. Calibrate the water activity meter as per the manufacturer’s instructions to ensure accurate readings.
3. Review the batch records to determine the appropriate sampling points for water activity testing, typically post-formulation and prior to packaging.

5.2 Sample Collection

1. Collect a representative sample of the cream formulation from the production batch. Ensure that the sample is homogenous and free from contamination.
2. Label each sample with the batch number, sample ID, sampling date, and sampling point to ensure traceability during testing.
3. Allow the sample to come to room temperature if necessary, as water activity measurements can be temperature-sensitive.

5.3 Water Activity Measurement Procedure

1. Place the sample in the water activity meter according to the manufacturer’s instructions. Ensure that the sample is placed properly in the sample chamber without contamination from external sources.
2. Follow the standard operating procedure for the water activity meter to ensure consistent and accurate readings. If using a digital water activity meter, ensure that the meter is calibrated and the reading is stable.
3. Allow the meter to equilibrate and stabilize before recording the reading. The reading should be recorded in water activity units (aw).
4. Take at least three readings per sample to ensure reliability and consistency. The average of the readings will be used for final data analysis.
5. Record the water activity measurement along with the sample information (e.g., batch number, test date, sample ID) in the Water Activity Measurement Log (Annexure-1).

5.4 Interpretation of Results

1. Compare the water activity measurements with the product specifications. The target water activity value will depend on the formulation and intended use of the cream, but typically, a water activity below 0.85 is considered desirable for cream formulations to prevent microbial growth.
2. If the water activity is within the acceptable range, mark the test as “Pass” in the Water Activity Measurement Log (Annexure-1) and proceed with the next stage of production or packaging.
3. If the water activity is outside the acceptable range, mark the test as “Fail.” Investigate the cause of the deviation, which may include issues with formulation, ingredient quality, or production processes.

5.5 Post-Test Activities

1. Record all test results, including batch number, sample ID, water activity readings, and any corrective actions taken, in the Water Activity Measurement Log (Annexure-1).
2. If the water activity is outside the acceptable range, initiate corrective actions such as formulation adjustments, improving production methods, or reviewing raw material specifications. Re-test the sample after corrective actions.
3. Submit the test results for review and approval by the QA team to ensure compliance with internal and regulatory standards.

5.6 Documentation and Record-Keeping

1. Ensure that all water activity testing records are complete, accurate, and securely stored. This includes the Water Activity Measurement Log (Annexure-1) and the Deviation Log (Annexure-2) for failed tests.
2. Retain all records for a minimum of two years or as required by regulatory guidelines.
3. Ensure that records are reviewed and approved by the Quality Assurance team to verify compliance with GMP standards and regulatory requirements.

6. Abbreviations

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

7. Documents

1. Annexure-1: Water Activity Measurement Log
2. Annexure-2: Deviation Log

8. References

• Good Manufacturing Practices (GMP) Guidelines – 21 CFR Part 211
• International Conference on Harmonisation (ICH) Q7 – Good Manufacturing Practice for Active Pharmaceutical Ingredients
• Pharmacopeial Monographs for Water Activity Measurement

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Water Activity Measurement Log

Batch Number	Sample ID	Sampling Date	Water Activity (aw)	Operator
12345	S-001	21/01/2026	0.85	John Doe

Annexure-2: Deviation Log

Deviation Date	Batch Number	Deviation Description	Corrective Action Taken	Operator
21/01/2026	12345	Water activity above specification	Adjusted formulation, re-tested	Jane Smith

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