Niosomes are non-ionic surfactant vesicles with an aqueous core, similar in structure to liposomes but composed of synthetic non-ionic surfactants.
This makes them more resistant to oxidative degradation compared to liposomes.
Structural Composition
Core and Bilayer: An aqueous core surrounded by bilayers of non-ionic surfactants.
Surfactants: Non-ionic surfactants with hydrophilic heads and hydrophobic tails, forming bilayers in water.
Cholesterol: Incorporated to regulate membrane fluidity and stability.
Types of Niosomes
Small Unilamellar Vesicles (SUVs): Single bilayer, small-sized vesicles.
Large Unilamellar Vesicles (LUVs): Single bilayer, larger vesicles.
Multilamellar Vesicles (MLVs): Multiple concentric bilayers.
Preparation Methods
Thin Film Hydration: Forms a surfactant film by solvent evaporation, followed by hydration.
Microfluidization: Applies force to mix surfactant and aqueous phases, forming vesicles.
Sonication: Uses ultrasonic waves to generate niosomes from a surfactant mixture.
Applications
Drug Delivery: Encapsulates hydrophilic and lipophilic drugs, enabling controlled release, improved bioavailability, and targeted delivery.
Dermatology: Enhances transdermal drug absorption for improved skin penetration.
Diagnostics: Carries diagnostic agents for imaging and diagnostic procedures.
Cosmetics: Moisturizing and hydrating properties make them useful in skincare products.
Advantages
Cost-Effective: Made from cheaper synthetic surfactants.
Enhanced Stability: More stable than liposomes, resistant to oxidation and hydrolysis.
Versatility: Capable of encapsulating both hydrophilic and hydrophobic drugs.
Improved Bioavailability: Enhances dissolution and absorption of poorly soluble drugs.
Controlled Release: Offers sustained drug release over extended periods.
Targeted Delivery: Can be modified for active targeting to specific cells or tissues.
Reduced Toxicity: Minimizes systemic toxicity by localizing drug delivery.
Disadvantages
Leakage and Fusion: Susceptible to drug leakage and vesicle fusion during storage.
Variable Drug Entrapment: Entrapment efficiency depends on preparation methods and drug properties.
Scaling Challenges: Large-scale production requires advanced methods and equipment.
Storage Issues: Requires specific storage conditions to prevent aggregation or leakage.
Irritation Potential: Some surfactants may irritate skin or mucous membranes, limiting use in certain applications.