Synthesis, characterization and drug release of biocompatible/biodegradable non-toxic poly(urethane urea)s based on poly(ε-caprolactone)s and lysine-based diisocyanate

Segmented poly(urethane urea)s (SPUUs) based on aliphatic diisocyanato (2,6-diisocyanato methyl caproate (lysine-based diisocyanate, LDI)), poly(ε-caprolactone diol)s (PCLs) with molecular weights 530, 1250 and 2000, and 1,4-butanediamine were synthesized in absence of catalyst. The resulting SPUUs, with different soft segment length, were characterized by suitable analytical techniques. The synthesized SPUUs had high molecular weights, low glass-transition temperatures (≤-15°C) and high elongation-at-break. The degradation of SPUUs in alkaline solution and in vitro drug release of sulfamethoxazole in pH 7.4 buffer were investigated. In addition, the degradation behavior of PCL1250-based SPUU was investigated by exposing to a buffer solution and biochemical oxygen demand (BOD) tests in an activated sludge. The drug release data was analyzed by an empirical equation ((M_t/M∞)=ktⁿ ). Finally, NIH3T3 fibroblasts have been used for cell-adhesion studies on these materials to investigate the biocompatibility. The synthesized SPUUs combine physical and bioresponsive and biodegradable properties that might be employed in wound dressing, drug delivery and tissue-engineering applications.