Synthesis, characterization of 2-(methacryloyloxy)ethyl-(di-) L-lactate and their application in dextran-based hydrogels

This paper describes the synthesis and characterization of 2-(methacryloylo xy) ethyl-L-lactate and 2-(methacryloyloxy)ethyl-di-L-lactate. These compou nds were obtained by reaction of L-lactide and 2-hydroxyethyl methacrylate (HEMA) at a molar ratio of 1:2 using stannous octoate as catalyst. After a purification step using preparative HPLC, the obtained products were charac terized by LH-NMR, HPLC and mass spectrometry. 2-(Methacryloyloxy)ethyl-(di -)lactate as well as HEMA were grafted to dextran using 1,1'-carbonyldiimid azole as coupling agent resulting in dex-(lactate)(1,2)-HEMA and dex-HEMA, respectively. Hydrogels were obtained by radical polymerization of aqueous solutions of the methacrylated dextrans. Due to the presence of hydrolytica lly sensitive groups in the crosslinks, these hydrogels degraded when expos ed to an aqueous solution (pH 7.2, 37 degrees C). For hydrogels with a fixe d crosslink density, the degradation times were 30, 12 and 6 days for dex-H EMA, dex-lactate-HEMA and dex-(lactate)(2)-HEMA hydrogels, respectively. Th is demonstrates that the degradation rate and time of dextran hydrogels can be tailored by the length of the spacer in the crosslink of the hydrogels. (C) 1999 Elsevier Science Ltd. All rights reserved.