Preparation of Nanoliposomes for Drug Delivery
1) Purpose
This SOP outlines the procedure for preparing nanoliposomes for drug delivery applications. Nanoliposomes are nanoscale lipid-based vesicles that encapsulate drugs, improving their bioavailability and targeted delivery. This technique is critical for developing advanced drug formulations with enhanced stability, controlled release, and targeted delivery properties.
2) Scope
This SOP applies to all personnel involved in the preparation of nanoliposomes for drug delivery. It includes steps for preparing lipid suspensions, size reduction using techniques like high-pressure homogenization or sonication, and encapsulating drugs within the nanoliposomes.
3) Responsibilities
- Operators: Responsible for preparing lipid suspensions, performing size reduction, and ensuring proper encapsulation of the drug in nanoliposomes.
- QA Team: Responsible for reviewing the batch records and ensuring the process complies with SOP guidelines.
- QC Team: Responsible for performing quality control tests to confirm the size, encapsulation efficiency, and stability of nanoliposomes.
4) Procedure
4.1 Equipment Setup
Ensure that the necessary equipment is properly calibrated and set up before the preparation of nanoliposomes.
4.1.1 Required Equipment
- High-pressure homogenizer or sonicator
- Rotary evaporator
- pH meter
- Temperature-controlled water bath
- Particle size analyzer (DLS)
4.1.2 Equipment Calibration
- 4.1.2.1 Calibrate the high-pressure homogenizer or sonicator, ensuring the pressure or amplitude settings are accurate.
- 4.1.2.2 Verify the pH meter using standard buffer solutions (pH 4.0, 7.0, and 10.0).
- 4.1.2.3 Confirm that the rotary evaporator is functioning properly, and the water bath maintains the required temperature for lipid hydration.
4.2 Lipid Film Preparation
The lipids must be dissolved and prepared for nanoliposome formation through size reduction techniques such as sonication or high-pressure homogenization.
- 4.2.1 Weigh the required amount of lipids (e.g., phospholipids and cholesterol) as specified in the formulation protocol. Record the weights in the Batch Manufacturing Record (BMR).
- 4.2.2 Dissolve the lipids in an appropriate organic solvent such as chloroform or ethanol 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 residual solvent.
4.2.5 Hydration of Lipid Film
- 4.2.5.1 Hydrate the lipid film by adding the pre-warmed aqueous phase (e.g., phosphate-buffered saline or drug solution) to the flask.
- 4.2.5.2 Stir the mixture gently for 30 minutes to ensure complete hydration of the lipid film and formation of multilamellar vesicles (MLVs).
4.3 Size Reduction and Nanoliposome Formation
The lipid suspension is subjected to high-pressure homogenization or sonication to achieve size reduction and form nanoliposomes.
- 4.3.1 If using a high-pressure homogenizer, set the pressure between 500 and 1500 bar and pass the lipid suspension through the homogenizer for 5 to 10 cycles to achieve nanometer-sized liposomes.
- 4.3.2 If using a sonicator, immerse the lipid suspension in the sonicator bath and set the sonication amplitude to the desired level. Sonicate for 5 to 30 minutes, depending on the target nanoliposome size.
- 4.3.3 Monitor the temperature of the lipid suspension during sonication or homogenization to prevent overheating. Ensure the temperature does not exceed 40°C.
4.4 Drug Encapsulation in Nanoliposomes
Drugs or active ingredients can be encapsulated in nanoliposomes either during the lipid hydration step or post-nanoliposome formation.
- 4.4.1 Dissolve the drug or active ingredient in the aqueous phase before lipid hydration if it is water-soluble.
- 4.4.2 For lipophilic drugs, dissolve the drug in the lipid-solvent mixture before forming the lipid film.
- 4.4.3 If the drug is to be encapsulated after nanoliposome formation, mix the nanoliposome suspension with the drug solution and allow the drug to be absorbed into the lipid bilayer or interior.
4.5 Quality Control
Perform the following quality control tests to confirm the size, encapsulation efficiency, and stability of the nanoliposomes:
- 4.5.1 Measure the particle size of the nanoliposomes using dynamic light scattering (DLS) or a similar particle sizing method.
- 4.5.2 Evaluate the encapsulation efficiency by analyzing the concentration of the encapsulated drug or active ingredient in the nanoliposome suspension.
- 4.5.3 Assess the stability of the nanoliposomes by storing them at specified conditions and monitoring their size, morphology, and drug retention over time.
4.6 Storage of Nanoliposomes
Once the nanoliposomes are prepared and quality control tests have been performed, store them under appropriate conditions to maintain stability.
- 4.6.1 Transfer the nanoliposome suspension to sterilized, airtight containers and store them at 4°C or as specified in the formulation protocol.
- 4.6.2 Ensure that all storage containers are labeled with the batch number, preparation date, and storage conditions.
- 4.6.3 Periodically test the stored nanoliposomes for size, stability, and drug retention to ensure they remain within specification throughout their shelf life.
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 Nanotechnology in Drug Delivery
- 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 | Size Reduction Technique | Encapsulation Method | Operator Initials | QA Signature |
|---|---|---|---|---|---|---|---|
| Batch Number | Lipid Name | Weight in grams | Buffer/Drug Solution | Homogenization/Sonication | Pre-hydration/Post-formation | Operator Name | QA Name |
