Standard Operating Procedure for Designing Stability-Indicating Formulations
| Department | Product Development |
|---|---|
| SOP No. | SOP/SIM/111/2025 |
| Supersedes | SOP/SIM/111/2022 |
| Page No. | Page 1 of 12 |
| Issue Date | 18/06/2025 |
| Effective Date | 20/06/2025 |
| Review Date | 18/06/2026 |
1. Purpose
To establish a procedure for designing stability-indicating formulations for sterile injectable products that ensure product quality, safety, and efficacy over its intended shelf life.
2. Scope
This SOP applies to the formulation development team involved in the design and evaluation of sterile injectable products under stability study protocols, covering early-phase development through final formulation
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3. Responsibilities
- Formulation Scientist: Responsible for designing and evaluating formulation stability.
- Analytical Scientist: Develop and validate stability-indicating methods.
- QA Department: Ensure documentation and review of stability results.
4. Accountability
Head – Product Development and Head – QA shall be accountable for compliance with this SOP.
5. Procedure
5.1 Preformulation Studies
- Review physicochemical properties of the drug substance (solubility, pKa, logP, hygroscopicity).
- Conduct compatibility screening with potential excipients under stress conditions.
- Evaluate pH stability and solubility range to select optimal buffer system.
5.2 Design of Formulation
- Select stabilizers, antioxidants, pH modifiers, tonicity agents, and surfactants based on drug profile.
- Formulate 3–5 pilot batches with varied excipient concentrations.
- Filter-sterilize or aseptically prepare formulations and fill in appropriate primary packaging (vial, PFS).
5.3 Stability Study Protocol
- Follow ICH Q1A(R2) guidelines for stability testing.
- Recommended conditions:
- 25°C ± 2°C / 60% RH ± 5% RH (long-term)
- 30°C ± 2°C / 65% RH ± 5% RH (intermediate)
- 40°C ± 2°C / 75% RH ± 5% RH (accelerated)
5.4 Analytical Evaluation
- Stability indicating parameters:
- Appearance, pH, assay, degradation products
- Particulate matter, sub-visible particles
- Sterility and endotoxin (where required)
- Use validated stability-indicating HPLC or UV methods.
5.5 Data Review and Interpretation
- Summarize trends and OOT/OOS occurrences.
- Formulation selected must meet all critical quality attributes through the defined shelf life.
- Prepare summary report with statistical evaluation of data.
6. Abbreviations
- ICH: International Council for Harmonisation
- RH: Relative Humidity
- OOT: Out of Trend
- OOS: Out of Specification
- PFS: Prefilled Syringe
7. Documents
- Formulation Development Worksheet – Annexure-1
- Stability Study Protocol Template – Annexure-2
- Stability Data Summary Table – Annexure-3
8. References
- ICH Q1A(R2) Stability Testing of New Drug Substances and Products
- FDA Guidance for Industry: Stability Testing of Drug Substances
9. SOP Version
Version: 2.0
10. Approval Section
| Prepared By | Checked By | Approved By | |
|---|---|---|---|
| Signature | |||
| Date | |||
| Name | |||
| Designation | Formulation Scientist | QA Executive | Head QA |
| Department | Product Development | Quality Assurance | Quality Assurance |
11. Annexures
Annexure-1: Formulation Development Worksheet
Document covering formulation trials, excipients used, and rationale for selection.
Annexure-2: Stability Study Protocol Template
Template including storage conditions, time points, test parameters, and sample pull schedule.
Annexure-3: Stability Data Summary Table
| Time Point | Storage Condition | Assay (%) | Degradation (%) | Appearance | pH |
|---|---|---|---|---|---|
| 0M | 25°C/60% RH | 100.0 | 0.0 | Clear | 6.8 |
| 6M | 25°C/60% RH | 98.2 | 0.5 | Clear | 6.7 |
Revision History
| Revision Date | Revision No. | Details | Reason | Approved By |
|---|---|---|---|---|
| 12/01/2022 | 1.0 | Initial version | New SOP | QA Head |
| 18/06/2025 | 2.0 | Expanded to include Annexures and ICH harmonization | Periodic Review | QA Head |