Tunable release of ophthalmic therapeutics from injectable, resorbable, thermoresponsive copolymer scaffolds

The sustained release of ophthalmic therapeutics to the posterior segment of the eye is a challenge. Injectable polymer materials have the potential to reduce injection frequency by providing long term therapeutic delivery. Copolymers with varying N-isopropylacrylamide, acrylamide (AAm), acrylic acid N-hydroxysuccinimide, and (r)-α-acryloyloxy-β,β-dimethyl-γ-butyrolactone (DBA) were synthesized by RAFT polymerization to develop injectable, resorbable, and thermoresponsive copolymer scaffolds. Upon injection into physiological conditions, these copolymers undergo a temperature induced gelation to form a drug releasing scaffold. Modification of the copolymer's AAm/DBA ratio and molecular weight afforded significant and precise control over the scaffold's physical properties and subsequent drug release profile. Hydrolytic DBA ring-opening enables redissolution of the copolymers for clearance from the body. Precise control over the drug release profile from these copolymer scaffolds by simple alteration of composition and molecular weight provides an efficient method to customize the minimally invasive delivery of therapeutics to the posterior segment of the eye. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 53-62, 2017.