Pharmacology: Cap: Glucosamine is a natural substance found in chitin, mucoproteins, and mucopolysaccharides. It is involved in the manufacture of glycosaminoglycan, which forms cartilage tissue in the body; glucosamine is also present in tendons and ligaments. Glucosamine must be synthesised by the body but the ability to do this declines with age. Glucosamine and its salts have therefore been advocated in the treatment of rheumatic disorders including osteoarthritis.
Glucosamine also acts to improve the viscosity of synovial fluid by increasing synovial fluid production, thereby providing lubricant activity.
Absorption: After oral administration, bioavailability is low due to first-pass hepatic metabolism ~26%. The gastrointestinal absorption is close to 90%.
Distribution: Glucosamine is not protein-bound, but rather incorporates into plasma proteins (primarily globulins). Volume of Distribution: 2.5 Liters.
Metabolism: Liver, extensive. The first-pass effect in the liver in which more than 70% of glucosamine is metabolized.
Excretion: Renal Excretion, 10%. Feces, 11%. Part of a dose of glucosamine sulfate is eliminated as carbon dioxide via expired air.
Powd for oral soln: Glucosamine is a natural amino monosaccharide and a basic building block for the biosynthesis of glycoprotein, glycolipids, hyaluronic acid, glycosaminoglycans and proteoglycans, which are important constituents of the articular cartilage. Glucosamine is important for maintaining the elasticity, strength and resilience of cartilage in joints. This helps to reduce damage to the joints.
In addition to supporting cartilage and other connective tissue, Glucosamine enhances the production of hyaluronic acid and enhances the anti-inflammatory action of this molecule. The administration of Glucosamine is believed to stimulate production of cartilage components and allow rebuilding of damaged cartilage.
About 90% of Glucosamine administered orally as a Glucosamine salt gets absorbed from the small intestine, and from there it is transported via the portal circulation to the liver. It appears that a significant fraction of the ingested Glucosamine is catabolized by first-pass metabolism in the liver. Following oral administration, Glucosamine Sulphate is rapidly desulphated and metabolized to smaller molecules and ultimately to carbon dioxide, water, and urea. Glucosamine is not protein-bound but rather incorporates into plasma proteins (primarily globulins). About 10% of the oral administered dose is excreted in the urine and approximately 11% is excreted in the faeces as unabsorbed drug. Also, Glucosamine is partly eliminated as carbon dioxide in expired air via lungs. Glucosamine incorporated into plasma proteins has an elimination half-life of around 68 hours after oral administration.