Drug Loaded Liposomes 

Drug-loaded liposomes are nanoscale vesicles composed of one or more phospholipid bilayers encapsulating an aqueous core. They are engineered to carry therapeutic agents, improving drug solubility, bioavailability, and targeted delivery while reducing systemic toxicity. 

Technical Content

• Structure and Composition:
  • Phospholipid Bilayer: Liposomes consist of amphiphilic phospholipids arranged in bilayers. The hydrophobic tails face inward, forming the bilayer, while the hydrophilic head groups interact with the aqueous environment.
• Synthesis and Drug Loading Techniques:
  • Thin-Film Hydration: Phospholipids and cholesterol are dissolved in an organic solvent, which is evaporated to form a thin film. Hydration with an aqueous drug solution leads to vesicle formation. Sonication or extrusion then reduces vesicle size and yields more uniform liposomes.
• Characterization and Surface Engineering:
  • Size and Lamellarity: Techniques such as dynamic light scattering (DLS), transmission electron microscopy (TEM), and cryo-electron microscopy (cryo-EM) characterize liposome size, distribution, and lamellarity (number of bilayers).

Applications

• Cancer Therapy:
  Liposomes encapsulating chemotherapeutics (e.g., doxorubicin, paclitaxel) improve drug accumulation in tumors while minimizing off-target toxicity. FDA-approved formulations like Doxil® demonstrate clinical success through enhanced efficacy and reduced side effects.
• Infectious Diseases:
  Antibiotics and antiviral agents loaded in liposomes enhance delivery to infected cells, improve pharmacokinetics, and reduce resistance by achieving higher localized concentrations.
• Gene Therapy and Vaccines:
  Liposomes can transport nucleic acids (DNA, RNA) or antigens, protecting them from degradation and facilitating cellular uptake, playing a role in vaccine delivery and gene therapy strategies.

Drug-loaded liposomes represent a highly adaptable platform for therapeutic delivery, combining biocompatibility with tunable physical and chemical properties. Through careful design of lipid composition, surface modifications, and loading strategies, these nanocarriers optimize drug stability, controlled release, and targeted delivery, addressing key challenges in modern medicine.