Fig. 1

In vitro properties of the pCBAA-DEX polymer-drug conjugate: (A) pCBAA-DEX was synthesized via co-polymerization of CBAA and a DEX comonomer via free radical polymerization. (B) Previous studies have found good cartilage penetration and retention properties for pCBAA polymers, which was attributed to a small net positive polymer charge that enabled charge-interactions with the anionic GAGs. (C) pCBAA-DEX was found to continuously release DEX via hydrolytic cleavage of the linking ester over 3 weeks. In an inflammatory OA model, cartilage explants treated with pCBAA-DEX were protected from GAG loss over three weeks. (D) At the cartilage surface, pCBAA polymers increased the hydrophilicity and decreased friction through the hydration lubrication mechanism.