Hyalgan Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism of Action: Hyalgan is a sterile, non-pyrogenic, viscous, aqueous buffered solution of a defined high molecular weight fraction of highly purified hyaluronic acid sodium salt (Hyalectin). Hyaluronic acid is an important component of the body's extracellular matrix and is present in a particularly high concentration in cartilage and synovial fluid. Endogenous hyaluronic acid provides viscosity and elasticity to synovial fluid, which is fundamental for its lubricating and shock absorbing properties, and it is essential for the correct structure of proteoglycans in articular cartilage. In osteoarthritis there is an insufficient amount of, and a change in the quality of, hyaluronic acid in synovial fluid and cartilage. The intra-articular administration of hyaluronic acid into arthritic joints with degenerating cartilage surfaces and pathologically altered synovial fluid improved joint functions.
The observed beneficial effects of exogenous hyaluronic acid may be related to its interactions with various components of the synovial cavity (synoviocytes and chondrocytes). In controlled clinical studies, treatment cycles with Hyalgan have been shown to ameliorate the symptoms of osteoarthritis for up to 6 months following the end of treatment.
Pharmacokinetics: Hyaluronic acid sodium salt (Hyalectin) administered intra-articularly is eliminated from the synovial fluid within 2 to 3 days. Pharmacokinetic studies have shown that it is quickly distributed to the synovial membrane. The highest concentrations of labelled hyaluronic acid have been detected in the synovial fluid and the articular capsule, followed by, in decreasing order, the synovial membrane, the ligaments and the adjacent muscle.
Hyaluronic acid in synovial fluid has been shown to be not significantly metabolised. Animal studies have shown that some degradation occurs in the tissue surrounding the joints, but the major site for metabolisation is the liver and excretion is mainly through the kidneys.
Toxicology: Preclinical Safety Data: Hyalectin (hyaluronic acid sodium salt) was tested in a standard range of toxicological tests, including mutagenicity and reproductive toxicity studies, and produced negative results throughout.