Freeze-Thaw Stability Testing of Liposome Formulations
1) Purpose
The purpose of this SOP is to describe the procedure for conducting freeze-thaw stability testing on liposome formulations. This type of testing assesses the impact of repeated freezing and thawing cycles on the physical and chemical stability of liposomes, ensuring that they maintain their integrity under temperature stress.
2) Scope
This SOP applies to all personnel involved in stability testing of liposome formulations. It outlines the preparation, storage, and evaluation of liposomes subjected to multiple freeze-thaw cycles to simulate transportation and storage conditions.
3) Responsibilities
- Formulation Scientists: Responsible for preparing liposome samples for freeze-thaw stability testing and ensuring sample uniformity.
- QC Team: Responsible for conducting freeze-thaw testing at defined intervals and documenting the results.
- QA Team: Responsible for reviewing the test results and ensuring compliance with GMP standards.
4) Procedure
4.1 Sample Preparation
- 4.1.1 Prepare liposome formulations in sterilized containers and ensure uniformity across all samples.
- 4.1.2 Label the samples with the batch number, preparation date, and storage conditions.
- 4.1.3 Store samples at -20°C to simulate freezing conditions for the first cycle of testing.
4.2 Freeze-Thaw Cycle Testing
The following steps outline the procedure for freeze-thaw stability testing:
- 4.2.1 Freezing Phase: Store the liposomal samples at -20°C for 24 hours to simulate freezing conditions. Ensure that all samples reach the target temperature.
- 4.2.2 Thawing Phase: Remove the liposome samples from the freezer and allow them to thaw at room temperature (25°C) for 4 hours. Ensure that all samples are completely thawed before proceeding.
- 4.2.3 Repeat Cycles: Repeat the freezing and thawing process for a total of 3-5 cycles, depending on the protocol.
4.3 Physical and Chemical Stability Tests
After completing the freeze-thaw cycles, perform the following tests to assess the stability of the liposome formulation:
- 4.3.1 Particle Size Distribution: Measure the particle size of the liposomes using dynamic light scattering (DLS) to assess any aggregation or size changes after freeze-thaw cycles.
- 4.3.2 Encapsulation Efficiency: Measure the encapsulation efficiency of the active pharmaceutical ingredient (API) using HPLC to determine if the freezing and thawing process has affected drug retention.
- 4.3.3 Zeta Potential: Measure the zeta potential to assess changes in the surface charge of the liposomes, which can indicate colloidal instability.
- 4.3.4 Visual Inspection: Perform a visual inspection of the liposomal suspension to detect any signs of phase separation, precipitation, or aggregation.
4.4 Data Recording and Analysis
- 4.4.1 Record all test results in the Freeze-Thaw Stability Test Report (see Annexure 1 for the template).
- 4.4.2 Compare the test results before and after the freeze-thaw cycles to identify any changes in physical or chemical stability.
- 4.4.3 Analyze the data to determine whether the liposome formulation can withstand freeze-thaw cycles without compromising product quality.
4.5 Acceptance Criteria
The liposome formulation is considered stable under freeze-thaw conditions if the following criteria are met:
- 4.5.1 Particle size remains within acceptable limits, with no significant aggregation or size increase.
- 4.5.2 Encapsulation efficiency remains above the predefined threshold, indicating minimal loss of the API.
- 4.5.3 Zeta potential values remain stable, indicating good colloidal stability.
- 4.5.4 No visible signs of phase separation, precipitation, or aggregation are observed.
5) Abbreviations
- DLS: Dynamic Light Scattering
- HPLC: High-Performance Liquid Chromatography
- QC: Quality Control
- QA: Quality Assurance
6) Documents
- Freeze-Thaw Stability Test Report
- Batch Manufacturing Record (BMR)
- Particle Size Analysis Report
- Zeta Potential Report
- Encapsulation Efficiency Report
7) References
- ICH Q1A: Stability Testing of New Drug Substances and Products
- FDA Guidelines for Liposomal Drug Products
8) SOP Version
Version 1.0
Annexure
Annexure 1: Freeze-Thaw Stability Test Report Template
| Time Point | Storage Condition | Particle Size (nm) | Encapsulation Efficiency (%) | Zeta Potential (mV) | Visual Inspection | Operator Initials |
|---|---|---|---|---|---|---|
| Initial | -20°C | 100-200 nm | 90% | -30 to -50 mV | No aggregation | Operator Name |
| After 1 Cycle | Room Temperature | 100-200 nm | 88% | -30 to -50 mV | No aggregation | Operator Name |