Controlled Ring-Opening Polymerization of Lactide and Glycolide

Functionalizing PLGA and PLGA Derivatives for Drug Delivery and Tissue Regeneration Applications

“…Thus, in the biomedical field, recently developed less toxic alternatives as zinc salts or complexes, or even enzymes, should be considered. [23,25] The ROP of lactide and glycolide to produce PLGA by the solventless melt approach should start with purified monomers. [18] Typically, the monomers and a solution of the catalyst are added to a round-bottomed flask and the mixture is left turning under heating in a silicon oil bath.…”

Study of ligand substituent effects on the rate and stereoselectivity of lactide polymerization using aluminum salen-type initiators

“…Metal alkoxides, for example, those of Al, Zn, Mg, Y, Ln, Sn(II), Sn(IV), Fe(II), and Fe(III), are typically used to catalyze the ROP of LA and related cyclic esters. Several reviews describing the mechanism of ROP and the types of initiators and catalysts have been published recently (22)(23)(24)(25)(26)(27).…”

Synthesis of highly functionalized oligo‐ and copolyesters from a carbohydrate lactone

“…Stannous octanoate (Sn(Oct) 2 ) and alcohol, including diol, initiating systems have been widely studied for polymerization of other lactones, for example, lactide or e-caprolactone, and are attractive due to their tolerance of functionality, high activity, and ease of use. 18 Tetra-Oacetyl-D-gluconolactone reacted with 1,4-butanediol and Sn(Oct) 2 , at 80 8C, to produce a low M n oligoester, in 8 h. The oligoester was isolated by column chromatography, which removed the initiator residues but resulted in some decomposition, in 30% yield. The oligoester comprised a mixture of compound 1 and dialdaric ester, 2, and trialdaric ester, 3 as established Figure S1 illustrates the structure of LZnEt), CH 2 Cl 2 , room temperature, 20 h. .…”

“…The pseudo first order rate constant, k app , (the gradient of the linear fit) is 6.57 3 10 À3 min À1 which compares well with other lactide polymerization initiators. 16,18 There is an initiation time of $14 min; it is proposed that this is required for the zinc alkoxide initiator to form by the reaction between the oligoester hydroxyl groups and LZnEt. The initiation was studied by the stoichiometric reaction between the oligoester and LZnEt, using 1 H NMR spectroscopy, and a diminution of the zinc ethyl peak at 0.42 ppm was observed, consistent with the formation of LZnOR, and the liberation of ethane.…”