Swelling behavior and controlled release of new hydrolyzable poly(ether urethane) gels derived from saccharide and L ‐lysine derivatives and poly(ethylene glycol)

New hydrolyzable gels bearing saccharide, L‐lysine, and poly(oxyethylene) moieties were prepared via polyaddition of methyl ß‐D‐glucofuranosidurono‐6,3‐lactone (1) and poly(ethylene glycol) PEG, Mn = 1000 with an L‐lysine derivative, methyl (S)‐2,6‐diisocyanatohexanoate (2), using dibutyltin dilaurate and triisocyanate 3 as a catalyst and a crosslinking agent, respectively. The swelling ratio and rate of hydrolysis of these gels in phosphate buffers increased with the content of PEG. Hydrolysis of these gels was enhanced by increasing the pH of phosphate buffer solution in the range from 5.5 to 8.0, while the gel having only repeating units derived from 1 and 2 but no PEG was hardly hydrolyzed in any buffer solutions (pH 5.5, 7.0, 8.0). The release of hydrophilic 5(6)‐carboxyfluorescein (CF) from these gels in buffer solution of pH 8.0 was faster than that of hydrophobic magnesium 8‐anilino‐1‐naphthalenesulfonate (ANS). The release of ANS from the gel was enhanced with the swelling caused by hydrolysis.