Non-clinical assessment of lubrication and free radical scavenging of an innovative non-animal carboxymethyl chitosan biomaterial for viscosupplementation: An in-vitro and ex-vivo study

OBJECTIVE: Lubrication and free radical scavenging are key features of biomaterials used for viscosupplementation (VS) of joints affected by osteoarthritis (OA). The objective of this study was to describe the non-clinical performance characterization of KiOmedine(®) CM-Chitosan, a non-animal carboxymethyl chitosan, in order to assess its intended action in VS and to compare it to existing viscosupplements based on crosslinked hyaluronan (HA) formulations. METHOD: The lubrication capacity of the tested viscosupplements (VS) was evaluated in-vitro and ex-vivo. In-vitro, the coefficient of friction (COF) was measured using a novel tribological system. Meanwhile, an ex-vivo biomechanical model in ovine hindlimbs was developed to assess the recovery of join mobility after an intra-articular (IA) injection. Free radical scavenging capacity of HA and KiOmedine(®) CM-Chitosan formulations was evaluated using the Trolox Equivalent Antioxidant Capacity (TEAC) assay. RESULTS: In the in-vitro tribological model, KiOmedine(®) CM-Chitosan showed high lubrication capacity with a significant COF reduction than crosslinked HA formulations. In the ex-vivo model, the lubrication effect of KiOmedine(®) CM-Chitosan following an IA injection in the injured knee was proven again by a COF reduction. The recovery of joint motion was optimal with an IA injection of 3 ml of KiOmedine(®) CM-Chitosan, which was significantly better than the crosslinked HA formulation at the same volume. In the in-vitro TEAC assay, KiOmedine(®) CM-Chitosan showed a significantly higher free radical scavenging capacity than HA formulations. CONCLUSION: Overall, the results provide a first insight into the mechanism of action in terms of lubrication and free radical scavenging for the use of KiOmedine(®) CM-Chitosan as a VS treatment of OA. KiOmedine(®) CM-Chitosan demonstrated a higher capacity to scavenge free radicals, and it showed a higher recovery of mobility after a knee lesion than crosslinked HA formulations. This difference could be explained by the difference in chemical structure between KiOmedine(®) CM-Chitosan and HA and their formulations.