release, and stability studies.

3. Responsibilities

• Quality Control Analyst: Perform assay testing and record results accurately.
• QC Supervisor: Review and approve results and ensure compliance with analytical methods.
• Quality Assurance: Verify data and ensure test compliance as per validation protocols.

4. Accountability

The Head of Quality Control is accountable for the proper execution and documentation of assay testing procedures for gel products.

5. Procedure

5.1 Sampling

1. Collect samples from at least three locations: top, middle, and bottom of the bulk gel batch.
2. Ensure samples are representative and properly labeled with batch number, date, and sampling point.

5.2 Reagents and Standards

1. Use reference standards of APIs with valid certificates of analysis (CoA).
2. Prepare dilutions as per standard test method (STM) or pharmacopoeial monograph.
3. Use validated solvents and reagents free from contaminants.

5.3 Equipment

• HPLC System with UV/Visible Detector
• Analytical balance (sensitivity 0.1 mg)
• Volumetric flasks, pipettes, and glassware

5.4 Sample Preparation

1. Weigh accurately a specified amount of gel as mentioned in the test method.
2. Dilute with appropriate solvent to extract the API.
3. Filter using a 0.45 µm membrane filter before injection into HPLC.

5.5 Analytical Method

1. Run system suitability using reference standard to ensure column efficiency, resolution, and reproducibility.
2. Inject test sample and reference standard solution in replicate.
3. Calculate API content using peak area comparison and standard concentration.

5.6 Acceptance Criteria

• Assay result must be within 95% to 105% of labeled claim or as per specification in approved STM.
• Relative standard deviation (RSD) between replicates must be <2%.

5.7 Documentation

1. Record data in the Assay Test Logbook and Analytical Worksheet.
2. Attach chromatograms, standard preparation details, and calculations.
3. Submit results for review and final approval.

6. Abbreviations

• API: Active Pharmaceutical Ingredient
• HPLC: High Performance Liquid Chromatography
• STM: Standard Test Method
• RSD: Relative Standard Deviation
• CoA: Certificate of Analysis

7. Documents

1. Standard Test Method – Annexure-1
2. Analytical Worksheet Format – Annexure-2
3. Assay Test Logbook Format – Annexure-3

8. References

• USP/NF Monographs for topical gel products
• ICH Q2(R1) – Validation of Analytical Procedures
• FDA Guidance for Industry: Analytical Procedures and Methods Validation

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation	Jr. Production Chemist	QA Executive	Head – Manufacturing
Department	Gel Manufacturing	Quality Assurance	Manufacturing

11. Annexures

Annexure-1: Standard Test Method (STM) Template

STM ID
Product Name
API
Sample Preparation Method
Mobile Phase
Column Type
Detection Wavelength
Flow Rate
Injection Volume
Run Time
Acceptance Criteria	95%–105%

Annexure-2: Analytical Worksheet Format

Date	Product Name	Batch No.	Sample ID	Standard Used	Peak Area	Result (%)	Remarks

Annexure-3: Assay Test Logbook Format

Date	Batch No.	Analyst Name	Sample Weight	Solvent	Test Performed	Result	Reviewed By
					Assay

Revision History

Revision Date	Revision No.	Details	Reason	Approved By
12/05/2022	1.0	Initial version released	New SOP	QA Head
02/06/2025	2.0	Updated STM template and added acceptance criteria range	Regulatory alignment	QA Head