does not inhibit microbial recovery, in accordance with USP <61> and <62> guidelines.

2. Scope

This SOP applies to the Analytical Method Development (AMD) department and microbiology laboratory for all product categories requiring microbial enumeration and specified organism testing, including tablets, capsules, ointments, and injectables.

3. Responsibilities

• Microbiologist: Executes and documents the suitability testing including inoculation, incubation, and enumeration.
• Analytical Scientist: Provides test samples and supports neutralizer selection based on formulation type.
• QA Officer: Verifies accuracy, calculations, and regulatory compliance of test records.
• Head – AMD: Reviews and approves the completed suitability testing protocol and results.

4. Accountability

The Head of Analytical Method Development is accountable for the verification of microbial test suitability across all sample types and ensuring compliance with pharmacopeial methods.

5. Procedure

5.1 Preparation of Cultures

1. Obtain certified cultures from recognized repositories (e.g., ATCC or MTCC).
2. Use the following organisms:
   • Bacillus subtilis (TAMC)
   • Candida albicans (TYMC)
   • Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella spp., Clostridium sporogenes
3. Prepare 10–100 CFU/mL suspensions by serial dilution in sterile saline or peptone water.
4. Verify CFU/mL count using spread plate method before proceeding.

5.2 Sample and Media Preparation

1. Prepare the test sample as per the recommended quantity (e.g., 1 g or 1 mL).
2. Prepare media as per USP <61>/<62>:
   • Plate Count Agar (PCA)
   • Sabouraud Dextrose Agar (SDA)
   • Selective media for specified organisms
3. Document in Annexure-1: Media and Sample Preparation Log.

5.3 Inoculation for Suitability Testing

1. Add a known number of microorganisms (not more than 100 CFU) to the product sample.
2. Inoculate parallel control media with the same quantity of microorganisms without sample.
3. Incubate plates under the following conditions:
   • TAMC: 30–35°C for 3–5 days
   • TYMC: 20–25°C for 5–7 days
   • Specified pathogens: As per selective media requirement
4. Record conditions in Annexure-2: Inoculation and Incubation Log.

5.4 Interpretation and Acceptance Criteria

1. Compare recovery from test sample with recovery from control plate.
2. Recovery must be ≥ 50% of control for all organisms.
3. If recovery is < 50%, optimize with:
   • Dilution of sample
   • Use of neutralizers (e.g., lecithin, polysorbate 80)
   • Alternative media or incubation conditions
4. Document results in Annexure-3: Suitability Testing Result Sheet.

5.5 Final Report

1. Summarize organism-wise recovery, sample interferences, neutralizer effectiveness, and test validation.
2. Include observations, deviations (if any), and corrective actions.
3. Submit report to QA and AMD Head for approval and filing.
4. Use Annexure-4: Suitability Testing Summary Report.

6. Abbreviations

• TAMC: Total Aerobic Microbial Count
• TYMC: Total Yeast and Mold Count
• CFU: Colony Forming Units
• SOP: Standard Operating Procedure
• USP: United States Pharmacopeia

7. Documents

1. Media and Sample Preparation Log – Annexure-1
2. Inoculation and Incubation Log – Annexure-2
3. Suitability Testing Result Sheet – Annexure-3
4. Suitability Testing Summary Report – Annexure-4

8. References

• USP <61> – Microbial Enumeration Tests
• USP <62> – Tests for Specified Microorganisms
• ICH Q6A – Specifications

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Media and Sample Preparation Log

Sample ID	Product	Media	Prepared By	Date
SUIT123-A	Tablet	PCA, SDA	Rajesh Kumar	18/05/2025

Annexure-2: Inoculation and Incubation Log

Organism	Inoculum Level	Test Plate	Control Plate	Incubation
B. subtilis	100 CFU	42 CFU	82 CFU	30°C / 3 days

Annexure-3: Suitability Testing Result Sheet

Organism	Recovery (%)	Acceptance Limit	Status
B. subtilis	51.2%	≥ 50%	Pass

Annexure-4: Suitability Testing Summary Report

All test organisms met the recovery requirement of ≥ 50%. Neutralizers were effective in preventing sample interference. Suitability testing method verified for tablets batch TB0525.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Updated acceptance criteria and annexure formats	Annual Review