Preparing Liposomes for Nasal Delivery

1) Purpose

The purpose of this SOP is to outline the procedure for preparing liposomes for nasal delivery. Nasal liposomes are used for delivering active pharmaceutical ingredients (APIs) directly to the nasal mucosa, enabling targeted drug delivery with potential systemic absorption. This formulation method is particularly useful for treatments involving neurological conditions or local nasal therapies.

2) Scope

This SOP applies to personnel involved in the formulation of liposomes for nasal delivery, with a focus on optimizing particle size, stability, and drug encapsulation. It also covers the preparation process, quality control testing, and storage of the final liposome product.

3) Responsibilities

• Formulation Scientists: Responsible for selecting appropriate lipids, APIs, and excipients for nasal delivery and maintaining batch documentation.
• QA Team: Responsible for reviewing formulation records and ensuring compliance with GMP standards.
• QC Team: Responsible for performing quality control tests, such as particle size analysis, encapsulation efficiency, and stability testing.

4) Procedure

4.1 Equipment Setup

The equipment required for preparing nasal liposomes must be properly cleaned, calibrated, and ready for operation. The following equipment is necessary:

4.1.1 Required Equipment

• Rotary evaporator
• Magnetic stirrer
• High-pressure homogenizer
• Ultrasonicator (optional for further size reduction)
• Dynamic light scattering (DLS) instrument for particle size analysis

4.1.2 Equipment Calibration

• 4.1.2.1 Ensure the rotary evaporator is calibrated for temperature and pressure control as per manufacturer’s specifications.
• 4.1.2.2 Calibrate the DLS instrument using particle size standards to ensure accurate measurement.

4.2 Selection of Lipid Components and APIs

The selection of lipid components and APIs is critical to ensure the successful formulation of liposomes for nasal delivery. Follow these steps to select the appropriate components:

• 4.2.1 Select lipids that are suitable for nasal mucosa penetration, such as phosphatidylcholine and cholesterol, to form the liposomal bilayer.
• 4.2.2 Choose an API that is stable in a liposomal formulation and is intended for nasal or neurological delivery. Hydrophilic drugs are encapsulated in the aqueous core, while lipophilic drugs are incorporated into the lipid bilayer.
• 4.2.3 Add surfactants or stabilizers, if necessary, to improve liposome stability and enhance the release of the API.

4.3 Liposome Preparation Process

4.3.1 Preparation of the Lipid Film

• 4.3.1.1 Weigh the required amounts of phospholipids and cholesterol according to the formulation protocol. Record the weights in the Batch Manufacturing Record (BMR).
• 4.3.1.2 Dissolve the lipids in an organic solvent, such as chloroform, in a round-bottom flask.
• 4.3.1.3 Use a rotary evaporator to evaporate the solvent under reduced pressure, forming a thin lipid film on the walls of the flask.
• 4.3.1.4 Dry the lipid film under vacuum for 30 minutes to remove residual solvent.

4.3.2 Hydration of the Lipid Film

• 4.3.2.1 Prepare an aqueous solution of the hydrophilic API or dissolve the lipophilic API in a small volume of organic solvent, depending on its solubility.
• 4.3.2.2 Add the API-containing solution to the lipid film and stir gently for 30 minutes to hydrate the lipids and form multilamellar vesicles (MLVs).
• 4.3.2.3 Maintain the temperature slightly above the phase transition temperature of the lipids (e.g., 45°C) during hydration to ensure effective liposome formation.

4.3.3 Size Reduction and Homogenization

• 4.3.3.1 Pass the MLV suspension through a high-pressure homogenizer to reduce the size and form small unilamellar vesicles (SUVs).
• 4.3.3.2 Optionally, use ultrasonication to further reduce the size, aiming for particles in the range of 100-200 nm for effective nasal absorption.

4.4 Quality Control Testing

After preparing the liposomes, perform quality control tests to ensure the API is properly encapsulated and the liposomes are stable for nasal delivery. The following tests are recommended:

• 4.4.1 Measure the particle size using dynamic light scattering (DLS). The average particle size should typically range between 100-200 nm for nasal delivery applications.
• 4.4.2 Evaluate the encapsulation efficiency of the API by measuring the amount of API encapsulated in the liposomes using appropriate analytical methods (e.g., HPLC).
• 4.4.3 Perform stability testing by storing the liposomes at different temperatures (e.g., 4°C, room temperature, 40°C) and monitoring particle size, API retention, and any phase separation over time.
• 4.4.4 Check the pH of the liposome suspension using a calibrated pH meter to ensure it is within the acceptable range for nasal application (typically pH 5.5-7.5).

4.5 Storage of Nasal Liposomes

The prepared nasal liposomes should be stored in sterilized, airtight containers. Label each container with the batch number, preparation date, and storage conditions. Store the liposomes at 4°C or as specified, and periodically test for stability and API retention.

5) Abbreviations, if any

• MLV: Multilamellar Vesicles
• SUV: Small Unilamellar Vesicles
• API: Active Pharmaceutical Ingredient
• DLS: Dynamic Light Scattering
• QA: Quality Assurance
• QC: Quality Control

6) Documents, if any

• Batch Manufacturing Record (BMR)
• Particle Size Analysis Report
• Encapsulation Efficiency Report
• Stability Test Report

7) References, if any

• ICH Q8: Pharmaceutical Development Guidelines
• FDA Guidelines for Nasal Drug Delivery Systems

8) SOP Version

Version 1.0

Annexure

Annexure 1: Batch Manufacturing Record Template

  

    
Batch No.
    
Lipid Type
    
Weight
    
API Name
    
API Concentration
    
Homogenization Time
    
Operator Initials
    
QA Signature
  
  

    
Batch Number
    
Lipid Name
    
Weight in grams
    
API Name
    
Concentration (mg/mL)
    
Minutes
    
Operator Name
    
QA Name