SOP for Preparation of Multilamellar Vesicles (MLVs)

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 solvent removal.
4.1.2.2 Verify the calibration of the pH meter using standard buffer solutions (pH 4.0, 7.0, and 10.0).

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

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