withdrawal, gliding force, and required injection pressure.

2. Scope

This SOP applies to the Analytical Method Development (AMD) and Formulation Development departments involved in characterizing prefilled syringes, suspensions, emulsions, and viscous injectable formulations.

3. Responsibilities

• Formulation Scientist: Selects formulation type and container-closure system for testing.
• Analytical Scientist: Designs syringeability and injectability testing methods, records force data.
• Lab Analyst: Operates texture analyzer or universal testing machine and performs evaluations.
• Head – AMD: Reviews and approves methods and data for GMP documentation and regulatory submissions.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring all injectability testing methods are robust, reproducible, and compliant with pharmacopeial and regulatory expectations.

5. Procedure

5.1 Equipment Required

1. Texture analyzer or universal testing machine with compression probe
2. Standard 1 mL or 3 mL disposable syringe (Luer-lock)
3. Needles: 22G, 25G, or appropriate for intended route
4. Chronometer or software for measuring time and force curves

5.2 Definitions

1. Syringeability: Ease with which the formulation can be aspirated into the syringe without clogging or bubble formation.
2. Injectability: Force required to expel the solution/suspension through a needle under controlled conditions.

5.3 Syringeability Testing

1. Prepare the formulation under test and ensure it’s at room temperature (25 ± 2°C).
2. Draw formulation into syringe using manual suction over 5–10 seconds.
3. Observe and record:
   • Resistance during withdrawal
   • Presence of air bubbles or clogging
   • Time taken to fill syringe
4. Document qualitative observations in Annexure-1: Syringeability Observation Log.

5.4 Injectability Testing

1. Attach filled syringe to a universal tester or texture analyzer with trigger probe at fixed speed (e.g., 100 mm/min).
2. Inject through needle into a receiver or collection chamber.
3. Measure and record:
   • Start-up force (N)
   • Gliding force (N)
   • Maximum force (N)
   • Total injection time (seconds)
4. Log all results in Annexure-2: Injectability Force Log.

5.5 Acceptance Criteria

1. No clogging or leakage during syringe filling or injection
2. Start-up and maximum injection force ≤ 20 N (unless formulation requires otherwise)
3. Smooth gliding with no interruptions in flow
4. Completion of injection within 10–15 seconds depending on viscosity

5.6 Method Validation

1. Perform validation across 3 formulations of varying viscosity (low, medium, high):
2. Parameters to validate:
   • Repeatability: RSD ≤ 10% for injection force
   • Robustness: Different operators and syringe types
   • Specificity: Detects flow resistance in high-viscosity samples
3. Summarize in Annexure-3: Validation Summary Sheet.

6. Abbreviations

• AMD: Analytical Method Development
• RSD: Relative Standard Deviation
• N: Newton
• SOP: Standard Operating Procedure

7. Documents

1. Syringeability Observation Log – Annexure-1
2. Injectability Force Log – Annexure-2
3. Validation Summary Sheet – Annexure-3

8. References

• USP <1384> – Injectability Testing
• EMA Guideline on Quality of Parenteral Products
• FDA Guidance for Industry – Nasal Spray and Injectable Drug Products
• ICH Q2(R2) – Validation of Analytical Procedures

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Syringeability Observation Log

Sample ID	Filling Time (sec)	Resistance	Comments	Analyst
INJ-45	6.3	Low	Free-flowing	Sunita Reddy

Annexure-2: Injectability Force Log

Sample ID	Start-up Force (N)	Max Force (N)	Injection Time (s)	Analyst
INJ-45	8.2	14.5	9.8	Rajesh Kumar

Annexure-3: Validation Summary Sheet

Parameter	Result	Criteria	Status
Precision	RSD = 6.1%	≤ 10%	Pass
Robustness	Consistent across syringe types	Qualitative Assessment	Pass

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Added acceptance criteria and updated annexure templates	Annual SOP Review