Liposomes, spherical vesicles composed of one or more phospholipid bilayers, have been widely used in various scientific disciplines since their discovery in the mid-1960s. They are particularly useful in drug delivery systems due to their biocompatibility, biodegradability, and ability to encapsulate both hydrophilic and lipophilic drugs. Liposomes can be classified into multilamellar vesicles (MLVs) and unilamellar vesicles (ULVs), with ULVs further divided into large unilamellar vesicles (LUVs) and small unilamellar vesicles (SUVs). The preparation methods of liposomes include passive and active loading techniques, such as mechanical dispersion, solvent dispersion, detergent removal, and reverse phase evaporation. These methods vary in their efficiency, encapsulation efficacy, and potential side effects. Liposomes can be modified to enhance their stability and circulation time, such as through the use of stealth liposomes coated with polyethylene glycol (PEG) or chitin derivatives. Liposomes are also used in various therapeutic applications, including cancer therapy, parasitic diseases, and infections, where they can reduce drug toxicity and improve efficacy. Despite their benefits, liposomes face challenges in stability and targeting, which are being addressed through advanced design and modification techniques. Overall, liposomes have established a significant role in modern drug delivery systems, offering improved pharmacokinetics and reduced toxicity compared to free drugs.Liposomes, spherical vesicles composed of one or more phospholipid bilayers, have been widely used in various scientific disciplines since their discovery in the mid-1960s. They are particularly useful in drug delivery systems due to their biocompatibility, biodegradability, and ability to encapsulate both hydrophilic and lipophilic drugs. Liposomes can be classified into multilamellar vesicles (MLVs) and unilamellar vesicles (ULVs), with ULVs further divided into large unilamellar vesicles (LUVs) and small unilamellar vesicles (SUVs). The preparation methods of liposomes include passive and active loading techniques, such as mechanical dispersion, solvent dispersion, detergent removal, and reverse phase evaporation. These methods vary in their efficiency, encapsulation efficacy, and potential side effects. Liposomes can be modified to enhance their stability and circulation time, such as through the use of stealth liposomes coated with polyethylene glycol (PEG) or chitin derivatives. Liposomes are also used in various therapeutic applications, including cancer therapy, parasitic diseases, and infections, where they can reduce drug toxicity and improve efficacy. Despite their benefits, liposomes face challenges in stability and targeting, which are being addressed through advanced design and modification techniques. Overall, liposomes have established a significant role in modern drug delivery systems, offering improved pharmacokinetics and reduced toxicity compared to free drugs.