Christopher Chen

Hyaluronic acid (HA) is a natural polysaccharide found within the synovial fluid of the joint space and is associated with the joint cartilage’s ability to mitigate friction and self-repair. Intra-articular injection of HA is a common treatment option for patients with osteoarthritis (OA) to reduce pain by improving the lubrication of the damaged joint. However, long-term relief of pain is difficult to achieve because HA breaks down over time, thus requiring repeated injections every 6 months. The objective of this study is to evaluate the potential of a synthetic block copolymer as a joint lubricant with a greater stability to replace HA. PA11 is a new amphiphilic block copolymer synthesized from short segments of polycaprolactone (PCL) and polyethylene glycol (PEG) at 1:1 ratio. The constituents of PA11 are both biocompatible and not toxic to the body. The lubricating characteristics of PA11 at various concentrations in water were evaluated by determining the coefficient of friction (COF) between two glass surfaces using a uniaxial mechanical test machine (TestResources). It was found that PA11 exhibited favorable frictional characteristics at a concentration of 1 g/mL in deionized water, which is comparable to HA at its clinical dose (20 mg/mL). PA11 at concentrations above or below 1 g/mL were not as lubricious compared with HA. There appears to be a correlation between the lubricity of PA11 solution with its viscosity, which is also concentration dependent. Overall, PA11 shows promise as a potential replacement of HA for OA treatment and further investigation is warranted.