Liposomes are nanoscale vesicles composed of lipid bilayers that can encapsulate both hydrophilic and hydrophobic drugs. Since their discovery in the 1960s, liposomes have been extensively studied and are considered one of the most successful drug-delivery systems. They are valued for their biological and technological advantages, including their ability to protect drugs from degradation, enhance their stability, and improve their targeting to specific tissues. Liposomes can be classified based on their preparation method, size, and lamellarity, with unilamellar vesicles (ULVs) and multilamellar vesicles (MLVs) being the most common types. ULVs are ideal for hydrophilic drugs, while MLVs are better suited for hydrophobic drugs. The physicochemical properties of liposomes, such as their size, surface charge, and lipid composition, significantly influence their behavior in the body. For example, smaller liposomes (50–450 nm) are more effective in targeting tumors due to the enhanced permeability and retention (EPR) effect, which allows them to pass through the tumor vasculature and accumulate in the tumor site. The addition of cholesterol to liposomes increases their stability and reduces their interaction with high-density lipoproteins (HDL) and low-density lipoproteins (LDL). PEGylation, which involves attaching polyethylene glycol (PEG) to the liposome surface, further enhances their stability and circulation time by preventing recognition by the reticuloendothelial system (RES). Liposomes have been used in various biomedical applications, including cancer treatment, where they have shown improved therapeutic indices and reduced toxicity compared to conventional drugs. For example, liposomal doxorubicin (Doxil) has been approved for the treatment of certain cancers due to its reduced cardiotoxicity. However, challenges remain in optimizing liposome formulations to achieve better drug delivery and minimize side effects. Strategies such as modifying the lipid composition, adjusting the size, and using targeted ligands have been explored to enhance the efficacy of liposomes. Despite these advancements, liposomes still face limitations in terms of drug release, targeting, and stability, which continue to be areas of active research.Liposomes are nanoscale vesicles composed of lipid bilayers that can encapsulate both hydrophilic and hydrophobic drugs. Since their discovery in the 1960s, liposomes have been extensively studied and are considered one of the most successful drug-delivery systems. They are valued for their biological and technological advantages, including their ability to protect drugs from degradation, enhance their stability, and improve their targeting to specific tissues. Liposomes can be classified based on their preparation method, size, and lamellarity, with unilamellar vesicles (ULVs) and multilamellar vesicles (MLVs) being the most common types. ULVs are ideal for hydrophilic drugs, while MLVs are better suited for hydrophobic drugs. The physicochemical properties of liposomes, such as their size, surface charge, and lipid composition, significantly influence their behavior in the body. For example, smaller liposomes (50–450 nm) are more effective in targeting tumors due to the enhanced permeability and retention (EPR) effect, which allows them to pass through the tumor vasculature and accumulate in the tumor site. The addition of cholesterol to liposomes increases their stability and reduces their interaction with high-density lipoproteins (HDL) and low-density lipoproteins (LDL). PEGylation, which involves attaching polyethylene glycol (PEG) to the liposome surface, further enhances their stability and circulation time by preventing recognition by the reticuloendothelial system (RES). Liposomes have been used in various biomedical applications, including cancer treatment, where they have shown improved therapeutic indices and reduced toxicity compared to conventional drugs. For example, liposomal doxorubicin (Doxil) has been approved for the treatment of certain cancers due to its reduced cardiotoxicity. However, challenges remain in optimizing liposome formulations to achieve better drug delivery and minimize side effects. Strategies such as modifying the lipid composition, adjusting the size, and using targeted ligands have been explored to enhance the efficacy of liposomes. Despite these advancements, liposomes still face limitations in terms of drug release, targeting, and stability, which continue to be areas of active research.