Preparation of Multilamellar Vesicles (MLVs)
1) Purpose
This SOP outlines the procedure for the preparation of multilamellar vesicles (MLVs) in liposome formulations. MLVs consist of multiple lipid bilayers and are commonly used in drug delivery systems, as they can encapsulate both hydrophilic and lipophilic drugs. This method is suitable for creating larger vesicles that provide controlled release of encapsulated materials.
2) Scope
This SOP applies to all personnel involved in the preparation of multilamellar vesicles (MLVs) in a laboratory or production setting. It includes lipid preparation, hydration, and analysis of the resulting vesicles.
3) Responsibilities
- Operators: Responsible for preparing MLVs according to the procedures described in this SOP and documenting all steps in the batch records.
- QA Team: Responsible for reviewing the batch records and ensuring that the preparation of MLVs is compliant with the SOP and regulatory guidelines.
- QC Team: Responsible for performing quality control tests to confirm the size, encapsulation efficiency, and stability of the MLVs.
4) Procedure
4.1 Equipment Setup
Ensure that all equipment is calibrated and ready for use before beginning the preparation of MLVs.
4.1.1 Required Equipment
- Rotary evaporator
- Magnetic stirrer
- Temperature-controlled water bath
- pH meter
- Particle size analyzer (DLS)
4.1.2 Equipment Calibration
- 4.1.2.1 Calibrate the rotary evaporator, ensuring that the temperature and vacuum settings are accurate for
4.2 Lipid Preparation
The lipid components of the MLVs must be dissolved and prepared for hydration to form multilamellar structures. Follow these steps for lipid preparation:
- 4.2.1 Weigh the required amount of lipids (e.g., phospholipids and cholesterol) according to the formulation protocol. Record the weights in the Batch Manufacturing Record (BMR).
- 4.2.2 Dissolve the lipids in an organic solvent, such as chloroform or methanol, in a round-bottom flask.
- 4.2.3 Evaporate the solvent using a rotary evaporator to form a thin lipid film on the inner surface of the flask.
- 4.2.4 Dry the lipid film under vacuum for 30 minutes to remove any remaining solvent.
4.3 Hydration of Lipid Film
The lipid film is hydrated with an aqueous phase to form multilamellar vesicles (MLVs). The following steps outline the hydration process:
- 4.3.1 Add the pre-warmed aqueous phase (e.g., buffer or drug solution) to the flask containing the dried lipid film.
- 4.3.2 Stir the suspension using a magnetic stirrer or vortex for 30 minutes to allow the lipid film to hydrate and form MLVs.
- 4.3.3 Ensure that the temperature of the water bath is set above the lipid phase transition temperature (typically 37°C) to facilitate proper hydration.
- 4.3.4 Adjust the pH of the aqueous phase as needed using the pH meter to maintain the stability of the MLVs and the encapsulated drug.
4.4 Quality Control of MLVs
Once the MLVs are prepared, perform the following quality control tests to assess their size, stability, and encapsulation efficiency:
- 4.4.1 Measure the particle size of the MLVs using dynamic light scattering (DLS) or another particle sizing method.
- 4.4.2 Test the encapsulation efficiency by analyzing the concentration of the drug or active ingredient encapsulated in the MLVs.
- 4.4.3 Evaluate the stability of the MLVs by storing them at the required conditions and monitoring their size and morphology over time.
5) Abbreviations, if any
- MLV: Multilamellar Vesicle
- DLS: Dynamic Light Scattering
- QA: Quality Assurance
- QC: Quality Control
6) Documents, if any
- Batch Manufacturing Record (BMR)
- Particle Size Analysis Report
- pH Calibration Log
7) References, if any
- FDA Guidelines for Liposomal Drug Products
- ICH Q7: Good Manufacturing Practice Guide
8) SOP Version
Version 1.0
Annexure
Annexure 1: Batch Manufacturing Record Template
| Batch No. | Lipid Type | Weight | Aqueous Phase | Hydration Time | Temperature | Operator Initials | QA Signature |
|---|---|---|---|---|---|---|---|
| Batch Number | Lipid Name | Weight in grams | Buffer/Drug Solution | Minutes | Temperature in °C | Operator Name | QA Name |