ICH standards.

2. Scope

This SOP is applicable to all formulation scientists, R&D personnel, and quality assurance teams involved in the development, evaluation, and documentation of subcutaneous injectable products within the sterile injectable manufacturing facility.

3. Responsibilities

• Formulation Scientist: Develops SC injection formulations, selects excipients, and prepares technical documentation.
• R&D Executive: Assists in trial batch preparation and data logging.
• Analytical Team: Performs pH, osmolality, and viscosity tests.
• QA Officer: Ensures that all formulation trials and documentation adhere to GMP requirements.

4. Accountability

The Head of Formulation Development is accountable for ensuring scientific and regulatory integrity in SC formulation development and implementation of this SOP.

5. Procedure

5.1 Pre-Formulation Evaluation

1. Evaluate the physicochemical properties of the API:
   • Solubility in water, buffers, and co-solvents
   • Stability under pH 4.0–7.4 (physiological range)
   • Compatibility with SC tissue components
2. Define the target dose volume (ideally ≤1.5 mL per SC site).
3. Select excipients with GRAS status and SC biocompatibility.

5.2 Formulation Strategy

1. Choose formulation type:
   • Clear aqueous solution
   • Micellar/colloidal dispersion
   • Prolonged-release depot using biodegradable polymers
2. Include:
   • Buffer system (e.g., phosphate buffer)
   • Isotonicity adjuster (e.g., sodium chloride, mannitol)
   • Viscosity modifier (e.g., HPMC, PEG) to control injectability
   • Preservative only for multi-dose formulations

5.3 Preparation of Trial Batches

1. Prepare lab-scale batches in a controlled cleanroom (Grade C or higher).
2. Ensure solution clarity, pH, and osmolality are within acceptable range (pH 5.5–7.0, ~300 mOsm/kg).
3. Filter through 0.22 µm sterile filters and fill into Type I glass vials or prefilled syringes.

5.4 In-vitro and Stability Testing

1. Test the following:
   • Clarity, color, pH, viscosity, osmolality
   • Sterility and endotoxin
   • Assay, degradation products, preservative content
2. Place on stability as per ICH Q1A:
   • Accelerated (40°C ± 2°C / 75% RH ± 5%)
   • Long-term (25°C ± 2°C / 60% RH ± 5%)

5.5 Documentation

1. Maintain complete records in the Formulation Development Dossier (Annexure-2).
2. Compile an Excipient Justification Report (Annexure-3).

6. Abbreviations

• SC: Subcutaneous
• API: Active Pharmaceutical Ingredient
• GRAS: Generally Recognized As Safe
• GMP: Good Manufacturing Practices
• ICH: International Council for Harmonisation

7. Documents

1. Stability Protocol for SC Injections – Annexure-1
2. Formulation Development Dossier – Annexure-2
3. Excipient Justification Report – Annexure-3

8. References

• ICH Q8(R2) – Pharmaceutical Development
• WHO Guidelines on Stability Testing of Pharmaceutical Products
• USP <1207> – Package Integrity Evaluation

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation	Formulation Scientist	QA Officer	Head – Formulation R&D
Department	R&D	Quality Assurance	Formulation Development

11. Annexures

Annexure-1: Stability Protocol for SC Injections

Batch No.	Condition	Interval	Test	Limit	Analyst
SC-DEV-003	25°C/60% RH	1M	pH	5.8–6.8	Rajesh Kumar

Annexure-2: Formulation Development Dossier

Batch ID	SC-DEV-003
Formulation	API Y in phosphate buffer
Final Concentration	20 mg/mL
Prepared By	Anita Deshmukh
Date	12/06/2025

Annexure-3: Excipient Justification Report

Excipient	Function	Justification
Mannitol	Isotonicity agent	Well-tolerated in SC formulations
Phosphate buffer	pH control	Maintains drug solubility and stability

Revision History

Revision Date	Revision No.	Details	Reason	Approved By
10/02/2022	1.0	Initial Issue	New SOP	QA Head
18/06/2025	2.0	Updated for clarity and annexures	Annual Review	QA Head