Active Targeting in Cancer Treatment

Active Targeting in Cancer Treatment

• Active targeting relies on the interaction between ligands on drug carriers and receptors on target cells to specifically target cancer cells.
• Nanoparticles are functionalized with antibodies that bind to receptors overexpressed on tumor cells, delivering chemotherapy drugs directly to the tumor site while sparing healthy tissues.

Targeting Levels

• First-order targeting: delivers drugs to the general vicinity of the target organ or tissue, e.g., administering drugs into the bloodstream to target organs like the liver or the brain.
• Second-order targeting: targets specific cells or regions within the target organ or tissue, e.g., directing drugs to tumor cells within the liver or targeting specific regions of the brain affected by neurological disorders.
• Third-order targeting: focuses on internalizing drugs into target cells through receptor-mediated processes, e.g., delivering drugs into cancer cells via receptor-mediated endocytosis, enhancing drug uptake and efficacy.
• Fourth-order targeting: aims for precise targeting at the molecular level within cells, e.g., targeting specific signaling pathways or organelles within cancer cells to disrupt tumor growth or induce apoptosis.

Strategies for Active Targeting

• Active targeting strategies involve modifying drug carriers to interact specifically with target cells, enhancing drug delivery precision and efficacy.

Targeting Approaches

• Stealth Approach: aims to escape the Reticuloendothelial System (RES) and prolong circulation time of drug carriers in the body.
• The stealth approach involves surface modification to enhance hydrophilicity, which reduces recognition by immune cells.
• An example of this is using polyethylene glycol (PEG) to coat the surface of nanoparticles, which reduces opsonization and phagocytosis by macrophages, allowing nanoparticles to remain in the bloodstream for a longer period and reach their target cells.