Synthesis of -Ornithine- and -Glutamine-Linked PLGAs as Biodegradable Polymers.

-ornithine and -glutamine are amino acids used for ammonia and nitrogen transport in the human body. Novel biodegradable synthetic poly(lactic--glycolic acid) derivatives were synthesized via conjugation with -ornithine or -glutamine, which were selected due to their biological importance. -ornithine or -glutamine was integrated into a PLGA polymer with EDC coupling reactions as a structure developer after the synthesis of PLGA via the polycondensation and ring-opening polymerization of lactide and glycolide. The chemical, thermal, and degradation property-structure relationships of PLGA, PLGA--ornithine, and PLGA--glutamine were identified. The conjugation between PLGA and the amino acid was confirmed through observation of an increase in the number of carbonyl carbons in the range of 170-160 ppm in the C NMR spectrum and the signal of the amide carbonyl vibration at about 1698 cm in the FTIR spectrum. The developed PLGA--ornithine and PLGA--glutamine derivatives were thermally stable and energetic materials. In addition, PLGA--ornithine and PLGA--glutamine, with their unique hydrophilic properties, had faster degradation times than PLGA in terms of surface-type erosion, which covers their requirements. -ornithine- and -glutamine-linked PLGAs are potential candidates for development into biodegradable PLGA-derived biopolymers that can be used as raw materials for biomaterials.