Nanoparticles in Drug Delivery

Nanoparticles in Drug Delivery

• Nanoparticles are small particles, sized 1-1000 nm, utilized in advanced drug delivery systems.
• Nanoparticles are a significant focus in advanced drug delivery due to their unique properties.
• Unique properties enhance drug effectiveness, reduce side effects, and improve targeting.

Key Factors in Nanoparticle Design

• Size (1-1000 nm) is crucial for cell uptake and targeting specific tissues.
• Surface charge, whether positive, negative, or neutral, and functionalization are key for interaction with biological systems.
• Functionalization targets specific cells or tissues.
• Shape influences how nanoparticles enter and move in the body.
• Spherical nanoparticles internalize more easily by cells.
• Rod-shaped particles may have different circulation times.

Types of Nanoparticles

• Liposomes & Niosomes encapsulate both hydrophilic and hydrophobic drugs and act as biocompatible carriers.
• Polymeric Nanoparticles are useful for controlled release and targeting.
• Solid Lipid Nanoparticles (SLNs) enhance solubility and drug release.
• Gold Nanoparticles are utilized in imaging and cancer treatment.
• Dendrimers are branched structures for precise drug loading.

Drug Release Mechanisms

• Passive Targetingaccumulates in tumors naturally due to the enhanced permeability and retention (EPR) effect.
• Active Targeting uses ligands, such as antibodies, to reach specific cells.
• Controlled Release responds to pH, temperature, or enzymes.

Challenges & Considerations

• Toxicity resulting from small size may cause unexpected interactions leading to cytotoxicity.
• Biodistribution must ensure correct targeting.
• Nanoparticles require stability in physiological conditions in the body.
• Regulatory Approval requires strict testing.

Applications in Medicine

• Cancer Therapy delivers chemotherapy directly to tumors.
• Gene Delivery transports DNA/RNA for gene therapy.
• Vaccines enhance immune response.
• Antibiotic Delivery improves drug effectiveness.
• Neurological Diseases treatments can cross the blood-brain barrier.

Commercial Examples

• Doxil® is liposomal doxorubicin for cancer treatment.
• Abraxane® is nanoparticle-bound paclitaxel for breast cancer treatment.

Nanoparticle Preparation: Top-Down Approaches

• Top-down methods involve breaking down larger particles or materials into smaller nanoparticles.
• High-Pressure Homogenization breaks down materials under pressure.
• Ball Milling uses mechanical grinding to reduce particle size.
• Laser Ablation uses laser to create nanoparticles from bulk material like metal, ceramic, or semiconductor.

Nanoparticle Preparation: Bottom-Up Approaches

• Bottom-up approaches involve assembling nanoparticles from molecular or atomic units, which allows for more control over particle properties.
• Solvent Evaporation forms polymeric nanoparticles by evaporating solvent from a solution containing the drug and a polymer.
• Emulsion Solvent Diffusion creates nanoparticles using an emulsion process.
• Precipitation Method / Solvent-antisolvent Method uses nanoprecipitation
• Coacervation or Phase Separation are also bottom-up approaches

Nanoparticle Preparation: Chemical Reactions

• Chemical reactions lead to nanoparticle formation.
• Chemical Vapor Deposition creates inorganic nanoparticles.
• Hydrothermal Synthesis is frequently used for the preparation of metal oxide nanoparticles, such as titanium dioxide and silica.
• Green Synthesis is used for the preparation of metal nanoparticles like gold and silver.

Nanoparticle Preparation: Electrostatic Methods and Electrospinning

• Electrostatic Methods assemble oppositely charged nanoparticles into larger structures by applying an electric field.
• Electrospinning is a technique where a polymer solution is subjected to an electric field to produce nanofibers or nanoparticles.