Tyrosine-derived polycarbonates incorporate two in vivo hydrolytically labile bonds in each repeat unit, a carbonate bond that connects the monomer units and an ester bond connecting a pendent chain. Degradation rate and products of the polymer are determined by the relative hydrolysis rate of these two labile bonds. Carbonate bond is hydrolysed at a faster rate than the pendent chain ester bond (). They, however, are relatively stable and degrade only very slowly in vitro. No mass loss has been detected after 3 years in vitro degradation (). Short-term in vivo studies (570 days) have confirmed less than 5% mass loss during degradation. Calculated from the decrease in molecular weight the degradation of PDTE carbonate to 5% of its initial molecular weight would take approximately 1890 days (). Tyrosine-derived polycarbonates were not found to be associated in ‘acid dumping’ or the release of acidic residues found during the degradation of poly(,-lactic acid) ().
This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology.
• Investigated the use of tyrosine-derived polycarbonate ..
In the process, it introduces the CuA center in four different systems---native protein systems, soluble protein truncates of native proteins, synthetic models using organic molecules, and biosynthetic models using proteins as ligands---with a greater emphasis on biosynthetic models of CuA, especially on new, deeper insights gained from their studies.
02/01/2014 · Asikainen A.J, et al
Here, tyrosine-derived polycarbonates, polyarylates, and polyethers are reviewed with special emphasis on recent developments relating to cellular and in vivo responses, sterilization techniques, surface characterization, drug delivery, and processing and fabrication techniques.