Biodegradation of random copolypeptide membranes consisting of N-hydroxyalkyl L-glutamine as one component

Two component random copolypeptide membranes, consisting of N-hydroxyalkyl L-glutamine and L-alanine or L-leucine were prepared by carrying out aminolysis reactions with 2-amino-1-ethanol (E) or 5-amino-1-pentanol (Pe), together with a cross-linking reaction with 1,8-octamethylenediamine (OMDA) on membranes of the starting copolymers consisting of gamma-benzyl L-glutamate (B) and L-alanine (A) or L-leucine (L). The relationships between their bulk structure and membrane properties were investigated, such as the swelling ratio in water, aqueous vapour permeability, tensile properties and enzymatic degradation behaviour of the membranes in a pseudo-extracellular fluid (PECF). The tensile properties of the hydrophilic membranes were highly dependent on the swelling ratio of PECF, and the hydrophobicity of the side chains, whose behaviour was typical of an elastomer. We showed that a common relation was obtained between the rate of water vapour permeability and the swelling ratio of membranes in PECF despite the difference of the nature of the side chains. Biodegradation of these membranes in vitro by bromelain indicated that the degradation was a bulk rather than a surface phenomenon, 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.