the Analytical Method Development (AMD) and Quality Control (QC) departments responsible for evaluating the physical characteristics of semi-solid topical formulations such as ointments during formulation development and stability studies.

3. Responsibilities

• Analytical Scientist: Performs spreadability testing using calibrated equipment and records data.
• QC Analyst: Assists in sample preparation and apparatus setup.
• QA Executive: Verifies test records and approves results based on pre-established specifications.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring the spreadability method is scientifically justified, validated, and aligned with regulatory expectations for product performance evaluation.

5. Procedure

5.1 Equipment and Materials

1. Glass slide apparatus (two glass slides with central marking)
2. Weight set (e.g., 250 g)
3. Stopwatch or timer
4. Spatula, scale, and ruler or calipers

5.2 Sample Preparation

1. Weigh 1 g of ointment sample and place it at the center of the lower glass slide marked with a circular boundary (typically 1 cm diameter).
2. Place the second glass slide on top of the ointment carefully to avoid air entrapment.

5.3 Spreadability Test

1. Place a 250 g weight centrally on the top glass slide.
2. Allow the weight to rest for a standard time (1–2 minutes).
3. Remove the weight and immediately measure the diameter of the spread circle using a ruler or digital calipers.
4. Repeat the procedure in triplicate and calculate the average spread diameter.

5.4 Calculation

Spreadability (g·cm/sec) = (Weight × Distance Spread) / Time

5.5 Acceptance Criteria

• Average spread diameter: Typically 5–7 cm (product-specific)
• RSD among replicates: ≤ 5%
• Consistent spreadability across batches indicates acceptable formulation consistency.

5.6 Method Validation

1. Repeatability: Triplicate spread diameter results within ±0.2 cm
2. Robustness: Validated by testing under variable ambient conditions (20–30°C)
3. Ruggedness: Results reproducible across analysts and test days

6. Abbreviations

• RSD: Relative Standard Deviation
• QA: Quality Assurance
• AMD: Analytical Method Development

7. Documents

1. Spreadability Test Log – Annexure-1
2. Validation Summary Report – Annexure-2

8. References

• WHO Technical Report Series for Semi-Solid Dosage Forms
• USP <1912>: Spreadability and Consistency Tests
• ICH Q6A: Specifications: Test Procedures and Acceptance Criteria

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Rupal Desai	Prakash Bhandari	Sunita Reddy
Designation	Analytical Chemist	QA Reviewer	Head – AMD
Department	Analytical Method Development	QA	Analytical Method Development

11. Annexures

Annexure-1: Spreadability Test Log

Sample ID	Weight (g)	Time (sec)	Diameter (cm)	Spreadability (g·cm/sec)	Status
ONT-259-01	250	60	6.2	25.83	Pass

Annexure-2: Validation Summary Report

The spreadability method was validated across three ointment batches and found reproducible (RSD = 2.1%). Spreadability was consistent between 6.1 to 6.3 cm. The method is robust, repeatable, and suitable for batch-to-batch comparison and formulation development.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
21/05/2025	2.0	Added robustness testing and updated annexures	Annual SOP Review	Sunita Reddy
01/04/2022	1.0	Initial Release	New SOP	QA Head