Background Hyaluronic acid plays a major role in the homeostasis of cartilage. In cases of osteoarthritis, hyaluronic acid is subjected to significant oxidative stress linked to the inflammation cascade leading to drastic diminution of its quantity at the level of the joint. This decrease in hyaluronic acid reduces dramatically the lubricating properties of the synovial fluid.

Several preparation methods have been developed to further stabilize the hyaluronic acid used as viscosupplement such as crosslinking or adding adjuvants.

Objectives A new formulation intended for intra-articular administration has been developed consisting of a combination of hyaluronic acid and vitamin B3 commonly called Niacinamide.

The addition of niacinamide has a protective effect against hyaluronic acid under heat stress and under oxidative stress.

Methods In order to assess the resistance to free radicals, 4 products were compared (HA 2.2%+vitamin B3 vs HA at 2.2% vs 2 cross-linked HA). 1 gram of sample were placed on Peltier Plate of a Rheometer – TA instrument and submitted to a temperature of 37°C. 50µL of H2O2 was introduced on the sample.

The rheological properties of the mixture were followed-up at a shear stress of 1Hz until full degradation of the sample (i.e. until reaching a viscosity close 0).

The degradation was calculated at each time point and plotted on a graph to compare the enzymatic degradation kinetics.

To assess the thermal resistance, 2 products were compared (HA 2.2%+ vitamin B3 vs HA 2.2%). The samples consisting of 2 grams of gel packaged in glass syringe were placed in a dry oven at 50°C. The viscosity was measured at 3 different timepoints.

Results This study demonstrates a significant better resistance to free-radical degradation for the HA+Niacinamide vs comparative products.

The viscosity follow-up under heat stress demonstrated that the adjunction of Niacinamide does have a positive effect in preserving the HA viscosity consistently throughout time.

Conclusion Vitamin B3 commonly called Niacinamide exhibits a dual positive effect when associated with Hyaluronic Acid.

The study demonstrates a better resistance to oxidative degradation for the HA+Niacinamide most probably due to the antioxidant effect of Niacinamide.

This study confirmed the adjunction of the Niacinamide into the HA-based gel formulation does increase the stability of HA against thermal degradation.

References Data on file

Disclosure of Interests Farid HADJAB Consultant of: Albomed GmbH, Grant/research support from: Albomed GmbH