Preclinical In Vivo Safety of Poly-Phosphorylated Superlubrication Vectors for the Treatment of Osteoarthritis.

Osteoarthritis (OA) can lead to a significant functional disability. Poly[2-(methacryloyloxy)ethyl phosphorylcholine] (pMPC) liposomes are a novel treatment modality for OA, intended to restore the natural lubrication properties of articular cartilage. Here, we report on two studies aimed to assess the local and systemic safety and toxicity of pMPCylated liposomes in comparison with physiological saline, in Sprague-Dawley (SD) rats and in sheep after a single intra-articular (IA) injection. The animals were sacrificed after 1 and 6 weeks (rats) and 3 and 6 weeks (sheep). No signs of toxicity or abnormal clinical findings were observed. Histopathological evaluation revealed no signs of reactivity or abnormal findings in the injected joints or in any other organs. In conclusion, a single IA injection of the pMPCylated liposomes demonstrated an excellent safety profile and did not result in local reactivity or systemic toxicity, thus supporting its further development for use in humans.