In the realm of drug delivery, nanomedicine involves packaging drugs into pharmaceutical vehicles that fall within the nanometer size range (10-200 nm). This process aims to enhance the drugs' physiochemical properties, such as solubility, stability, dissolution, pharmacokinetics, and tissue selectivity. These pharmaceutical vehicles, known as nanoparticles, include liposomes, micelles, polymeric nanoparticles, dendrimers, and macromolecules. Nanomedicine holds particular promise in tumor diagnosis and therapy due to a distinctive trait known as the enhanced permeability and retention (EPR) effect. This phenomenon allows nanoparticles to selectively penetrate tumor tissues through leaky vasculature while sparing normal tissues with more robust capillary structures. In contrast, small molecule drugs lack this selectivity, permeating both normal and cancerous tissues and often leading to significant side effects. 

 

Furthermore, the effectiveness of tumor-targeted drug delivery can be heightened through the conjugation of a targeting ligand, such as an antibody, onto nanoparticles. This ligand specifically recognizes surface receptors present on tumor cells, thereby enhancing the overall efficacy of the drug delivery system.  The tremendous promise of nanomedicine in non-invasive tumor imaging, early detection and drug delivery is evidenced with many products in clinical use and trials (Clinical Pharmacology & Therapeutics 2014). 

 

While nanoparticles offer potential for enhancing the water solubility and tissue selectivity of anticancer compounds, their delivery faces various biological barriers. Intravenously injected nanoparticles must evade reticuloendothelial (RES) and renal clearance, and maintain stability in plasma during systemic circulation to ensure adequate interaction with tumor physiology. Upon successful extravasation into the tumor compartment, nanoparticles encounter challenges navigating through the stroma against high interstitial fluid pressure (IFP) gradients, and eventually reaching target cells or releasing the drug payload for pharmacological effect. Therefore, meticulous design of nanoparticle formulations is crucial to surmount these barriers and achieve significant therapeutic efficacy. 

 

To overcome these barriers, one of the effective alternatives is to deploy lipid-based delivery systems.