Scope

This SOP applies to the Analytical Method Development and Quality Control departments for the evaluation of preservatives such as benzyl alcohol, phenol, methylparaben, and propylparaben in injectable dosage forms.

3. Responsibilities

• Analytical Chemist: Develops, executes, and validates the test method for preservative detection.
• QC Analyst: Conducts sample testing and documents observations.
• QA Executive: Ensures protocol adherence, reviews data, and approves the report.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring validated, accurate, and sensitive methods are in place for detecting preservatives in sterile multi-dose formulations.

5. Procedure

5.1 Target Analytes

• Benzyl alcohol
• Phenol
• Methylparaben
• Propylparaben

5.2 Sample Preparation

1. Withdraw 1 mL of the injectable solution using aseptic technique.
2. Transfer into a 10 mL volumetric flask and dilute with mobile phase (e.g., water:acetonitrile 60:40 v/v).
3. Filter the solution through a 0.45 µm membrane filter.

5.3 Standard Preparation

1. Prepare individual and mixed standard solutions of all target preservatives in mobile phase at known concentrations (e.g., 100 µg/mL).
2. Store under refrigeration (2–8°C) and protect from light.

5.4 Chromatographic Conditions (HPLC)

• Column: C18, 250 mm × 4.6 mm, 5 µm
• Mobile Phase: Water:Acetonitrile (60:40), adjusted to pH 3.0 with phosphoric acid
• Flow Rate: 1.0 mL/min
• Detection Wavelength: 254 nm
• Injection Volume: 20 µL

5.5 Identification and Quantification

1. Inject standard and sample solutions into HPLC.
2. Compare retention times and UV spectra for identification.
3. Quantify using external standard calibration curve method.

5.6 Acceptance Criteria

• Preservative must be present within 90%–110% of declared content.
• Retention time difference between standard and sample ≤ ±2%.
• No interfering peaks at retention time of target preservatives.

5.7 Method Validation Parameters

1. Specificity: Should clearly resolve preservatives from each other and from excipients.
2. Linearity: r² ≥ 0.999 in the range of 50–150 µg/mL.
3. Accuracy: Recovery between 98%–102% at three concentration levels.
4. Precision: RSD ≤ 2% for repeatability and intermediate precision.
5. LOD/LOQ: Determine using signal-to-noise ratio method.

6. Abbreviations

• HPLC: High Performance Liquid Chromatography
• RSD: Relative Standard Deviation
• LOD: Limit of Detection
• LOQ: Limit of Quantification
• QA: Quality Assurance

7. Documents

1. Preservative Identification Log – Annexure-1
2. Chromatograms Set – Annexure-2
3. Validation Summary Report – Annexure-3

8. References

• USP <51>: Antimicrobial Effectiveness Testing
• ICH Q2(R1): Validation of Analytical Procedures
• FDA Guidance on Preservative Content in Injectable Products

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name	Vinita Iyer	Narendra Joshi	Sunita Reddy
Designation	Analytical Scientist	QA Reviewer	Head – AMD
Department	Analytical Method Development	QA	Analytical Method Development

11. Annexures

Annexure-1: Preservative Identification Log

Sample ID	Preservative	Retention Time (min)	Declared (%)	Found (%)	Status
MDV-273-01	Benzyl Alcohol	4.82	0.9%	0.91%	Pass

Annexure-2: Chromatograms Set

Overlay chromatograms of standard and sample injections showing matched retention times and clean baseline separation for benzyl alcohol and methylparaben.

Annexure-3: Validation Summary Report

The HPLC method for identifying and quantifying preservatives in multi-dose vials was validated across five formulations. Accuracy, precision, and linearity criteria were successfully met. The method is suitable for routine and regulatory testing.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
21/05/2025	2.0	Added new preservatives to scope, updated annexures	Annual Review	Sunita Reddy
10/04/2022	1.0	Initial SOP Release	New SOP	QA Head