THE MOLECULAR-WEIGHT OF THERAPEUTIC HYALURONAN (SODIUM HYALURONATE) -HOW SIGNIFICANT IS IT

Various molecular weight hyaluronic acid (HA) preparations have been i njected into joints for the treatment of human and equine osteoarthrit is. A therapeutic advantage has been claimed for commercial products w ith a molecular weight in the range found in normal synovial fluid (SF ), compared to lower molecular weight products. But a correlation betw een molecular weight and efficacy is not borne out by an analysis of t he available literature on clinical results, SF viscosity, HA concentr ation, HA molecular weight and rate of synthesis in joint disease. It is proposed that the beneficial effect of injected HA in joint disease may be due to pharmacological rather than to physical properties.