BIODEGRADATION OF RANDOM COPOLYPEPTIDE MEMBRANES CONSISTING OF N-HYDROXYALKYL L-GLUTAMINE AS ONE-COMPONENT

Two component random copolypeptide membranes, consisting of N-hydroxya lkyl L-glutamine and L-alanine or L-leucine were prepared by carrying out aminolysis reactions with 2-amino-1-ethanol (E) or 5-amino-l-penta nol (Pe), together with a cross-linking reaction with 1,8-octamethylen ediamine (OMDA) on membranes of the starting copolymers consisting of gamma-benzyl L-glutamate (B) and L-alanine (A) or L-leucine (L). The r elationships between their bulk structure and membrane properties were investigated, such as the swelling ratio in water, aqueous vapour per meability, tensile properties and enzymatic degradation behaviour of t he membranes in a pseudo-extracellular fluid (PECF). The tensile prope rties of the hydrophilic membranes were highly dependent on the swelli ng ratio of PECF, and the hydrophobicity of the side chains, whose beh aviour was typical of an elastomer. We showed that a common relation w as obtained between the rate of water vapour permeability and the swel ling ratio of membranes in PECF despite the difference of the nature o f the side chains. Biodegradation of these membranes in vitro by brome lain indicated that the degradation was a bulk rather than a surface p henomenon, and that the rate of degradation was also highly dependent on the swelling ratio of samples and on the hydrophobicity of the side chains of samples.