Novel fluorescent copolyanhydrides as potential visible matrices for drug delivery

Two classes of fluorescent copolyanhydrides were synthesized by melt copolycondensation of the fluorophoric diacid, p-(carboxyethylformamido)benzoic acid (CEFB), with sebacic acid (SA) or N-trimellitylimidoglycine (TMA-gly). Alternate copolyanhydride based on SA and CEFB was also prepared by solution polycondensation of CEFB and sebacoyl chloride. 1H NMR spectra of the copolymers confirm their structures. Fluorescence was observed for all the copolymers, the intensity of which increases with the CEFB fraction. Either blue (ca. 429 nm) or green (ca. 520 nm) light can be emitted from the copolymers with the excitation of UV (356 nm) and visible (470 nm) light, respectively. The polymers were further fabricated to microsphere formulation, which can be clearly visualized by fluorescent microscopy.