The most efficient synthesis method for producing biodegradable polymers with controlled degradation rates and desirable physical properties suitable for biomedical applications like drug delivery systems is the ring-opening polymerization ROP of cyclic esters or lactones. This method allows for precise control over the molecular weight, composition, and architecture of the resulting polymers, which in turn can be tailored to achieve the desired degradation rates and physical properties.ROP can be initiated by various mechanisms, including anionic, cationic, and coordination-insertion processes. The choice of initiator and catalyst can significantly influence the polymerization kinetics, as well as the resulting polymer's properties. Some common initiators used in ROP include organometallic compounds, metal alkoxides, and metal complexes.The most widely studied and utilized biodegradable polymers for biomedical applications are polyesters, such as poly lactic acid PLA , poly glycolic acid PGA , and their copolymers, poly lactic-co-glycolic acid PLGA . These polymers can be synthesized by ROP of their corresponding cyclic esters, lactide, and glycolide.The degradation rate of these polymers can be controlled by adjusting the ratio of lactic acid to glycolic acid units in the copolymer, as well as by introducing other monomers or functional groups. The physical properties, such as mechanical strength, hydrophilicity, and crystallinity, can also be tailored by varying the molecular weight, composition, and architecture of the polymer.In summary, the ring-opening polymerization of cyclic esters or lactones is the most efficient synthesis method for producing biodegradable polymers with controlled degradation rates and desirable physical properties for biomedical applications like drug delivery systems. By carefully selecting the initiator, catalyst, and monomer composition, it is possible to create a wide range of biodegradable polymers with tailored properties for specific applications.