Superparamagnetic iron oxide nanoparticles (SPIONs) are promising drug delivery vehicles due to their unique magnetic properties. These nanoparticles, composed of γ-Fe₂O₃ (maghemite) or Fe₃O₄ (magnetite), range in size from 10 to 100 nm and are coated with biocompatible polymers like dextran or polyethylene glycol to enhance their blood circulation and drug delivery efficiency. SPIONs can be guided by an external magnetic field to their target site, enabling targeted drug delivery. They are also used as contrast agents in magnetic resonance imaging (MRI) and for hyperthermia treatments to destroy cancer cells. SPIONs have shown potential as nonviral gene vectors for delivering plasmids into cells. However, their use in biomedical applications requires addressing toxicological concerns such as altered gene expression, iron homeostasis, and oxidative stress. The review discusses the physicochemical characteristics of SPIONs, including their shape, size, surface properties, and coating, which influence their biodistribution, internalization, and toxicity. Various methods for preparing SPIONs, such as coprecipitation, microemulsion, and polyol techniques, are described. Coating SPIONs with polymers enhances their biocompatibility and reduces toxicity. Drug loading can be achieved through conjugation or encapsulation, with various strategies for linking drugs to SPIONs. SPIONs are used in targeted drug delivery, magnetic focusing, and magnetic cell separation. Their biodistribution and elimination from the body depend on factors such as particle size, surface charge, and coating. SPIONs are primarily excreted via the kidneys, with their clearance influenced by their physicochemical properties. SPIONs have shown promise in cancer therapy, particularly in targeted drug delivery and hyperthermia. However, their clinical application requires further research to ensure safety and efficacy.Superparamagnetic iron oxide nanoparticles (SPIONs) are promising drug delivery vehicles due to their unique magnetic properties. These nanoparticles, composed of γ-Fe₂O₃ (maghemite) or Fe₃O₄ (magnetite), range in size from 10 to 100 nm and are coated with biocompatible polymers like dextran or polyethylene glycol to enhance their blood circulation and drug delivery efficiency. SPIONs can be guided by an external magnetic field to their target site, enabling targeted drug delivery. They are also used as contrast agents in magnetic resonance imaging (MRI) and for hyperthermia treatments to destroy cancer cells. SPIONs have shown potential as nonviral gene vectors for delivering plasmids into cells. However, their use in biomedical applications requires addressing toxicological concerns such as altered gene expression, iron homeostasis, and oxidative stress. The review discusses the physicochemical characteristics of SPIONs, including their shape, size, surface properties, and coating, which influence their biodistribution, internalization, and toxicity. Various methods for preparing SPIONs, such as coprecipitation, microemulsion, and polyol techniques, are described. Coating SPIONs with polymers enhances their biocompatibility and reduces toxicity. Drug loading can be achieved through conjugation or encapsulation, with various strategies for linking drugs to SPIONs. SPIONs are used in targeted drug delivery, magnetic focusing, and magnetic cell separation. Their biodistribution and elimination from the body depend on factors such as particle size, surface charge, and coating. SPIONs are primarily excreted via the kidneys, with their clearance influenced by their physicochemical properties. SPIONs have shown promise in cancer therapy, particularly in targeted drug delivery and hyperthermia. However, their clinical application requires further research to ensure safety and efficacy.