throughout the dosage unit.

2. Scope

This SOP applies to the Analytical Method Development (AMD) and Quality Control (QC) departments for assessing content uniformity in topical semi-solid preparations during formulation development, technology transfer, and routine batch release.

3. Responsibilities

• Analytical Scientist: Conducts sampling and assay of API content across the sample matrix.
• QC Analyst: Prepares samples from different locations within the container or bulk.
• QA Executive: Verifies and reviews data for compliance with uniformity standards.

4. Accountability

The Head of Analytical Method Development is accountable for validating and implementing homogeneity testing procedures and ensuring the results meet internal and regulatory quality standards.

5. Procedure

5.1 Sampling Plan

1. Sample topical product from at least three distinct locations:
   • Top
   • Middle
   • Bottom
2. Each portion should be approximately 1 g of the formulation.
3. Samples should be collected using sanitized spatulas or sampling spoons to avoid contamination.

5.2 Sample Preparation

1. Transfer the sample into a volumetric flask.
2. Add suitable solvent (e.g., methanol or mixture of alcohol and water).
3. Sonicate for 15 minutes to extract the API.
4. Make up the volume and filter through 0.45 µm filter.

5.3 Standard Preparation

1. Weigh appropriate quantity of reference standard.
2. Dissolve and dilute to the concentration similar to the sample in a validated solvent.
3. Filter through 0.45 µm filter.

5.4 Analytical Method

1. Analyze samples using a validated HPLC or UV spectrophotometric method.
2. Compare the peak area or absorbance of samples against the standard.
3. Calculate the percentage content of API in each location.

5.5 Acceptance Criteria

• All samples should be within 90%–110% of the labeled claim.
• Relative Standard Deviation (RSD) across samples should not exceed 5%.
• No significant variation in API content across sample locations.

5.6 Method Validation Parameters

1. Precision: Intra- and inter-day variability should have RSD ≤ 2%
2. Accuracy: Recovery should range from 98% to 102%
3. Robustness: Confirmed by varying sonication time and solvent system

6. Abbreviations

• API: Active Pharmaceutical Ingredient
• RSD: Relative Standard Deviation
• QA: Quality Assurance
• AMD: Analytical Method Development

7. Documents

1. Homogeneity Test Log – Annexure-1
2. Chromatogram or Spectra Set – Annexure-2
3. Validation Summary Report – Annexure-3

8. References

• USP <905>: Uniformity of Dosage Units
• ICH Q2(R1): Validation of Analytical Procedures
• WHO TRS: Guidelines on Quality Control Testing of Pharmaceutical Products

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Anjali Bhatt	Varun Mehta	Sunita Reddy
Designation	Analytical Scientist	QA Reviewer	Head – AMD
Department	Analytical Method Development	QA	Analytical Method Development

11. Annexures

Annexure-1: Homogeneity Test Log

Sample ID	Top (%)	Middle (%)	Bottom (%)	RSD (%)	Status
TOP-265-01	98.6	99.1	98.9	0.25	Pass

Annexure-2: Chromatogram or Spectra Set

Attached HPLC chromatograms of top, middle, and bottom layer samples showing comparable peak profiles and retention times.

Annexure-3: Validation Summary Report

Method validated across three batches of topical creams with precision (RSD = 1.8%), accuracy (mean recovery = 99.4%), and robustness to minor method variations confirmed. Suitable for routine and developmental testing.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
21/05/2025	2.0	Updated sampling criteria and added validation log references	Annual Review	Sunita Reddy
10/04/2022	1.0	Initial SOP Release	New SOP	QA Head