Biodegradation hyaluronic acid

Hyalofast Anika therapeutics (Italy) Biodegradable hyaluronic acid—based scaffold used for the entrapment of mesenchymal stem cells Chondral and osteochondral lesions in the knee and ankle Marketed... 

Biodegradable polymers, both synthetic and natural, have gained more attention as carriers because of their biocompatibility and biodegradability and therewith the low impact on the environment. Examples of biodegradable polymers are synthetic polymers, such as polyesters, poly(orfho-esters), polyanhydrides and polyphosphazenes, and natural polymers, like polysaccharides such as chitosan, hyaluronic acid and alginates. 

Biodegradable hydrogels cross-linked with hyaluronic acid serve as inflammation-sensing systems. At sites of inflammation leukocytes and macrophages produce hydroxyl radicals, which specifically break down the hyaluronic acid cross-linking, thus aiding in drug release at the site of inflammation.47 48... 

Prestwich, G.D. et al., Controlled chemical modification of hyaluronic acid synthesis, applications, and biodegradation of hydrazide derivatives, J. Cont. Rel., 53, 93, 1998. 

In addition to synthetic biodegradable polymers discussed so far, naturally occurring biopolymers have also been used for fabricating implantable dmg delivery systems. Examples of natural biopolymers are proteins (e.g. albumin, casein, collagen, and gelatin) and polysaccharides (e.g. cellulose derivatives, chitin derivatives, dextran, hyaluronic acids, inulin, and starch). 

Several other biodegradable, biocompatible, injectable polymers are being investigated for drug delivery systems. They include polyvinyl alcohol, block copolymer of PLA-PEG, polycyanoacrylate, polyanhydrides, cellulose, alginate, collagen, gelatin, albumin, starches, dextrans, hyaluronic acid and its derivatives, and hydroxyapatite. ... 

There are many kinds of natural biodegradable polymers. They are classified into three types according to their chemical structures, i.e., polysaccharides, polypeptides/proteins and polynucleotides/nucleic acids. Among them, polysaccharides, such as cellulose, chitin/chitosan, hyaluronic acid and starch, and proteins, such as silk, wool, poly( y-glutamic acid), and poly(e-lysin), are well known and particularly important industrial polymeric materials. 

The book distills recent research conducted by the scientific community. It is arranged in four parts. Part I, Polysaccharides, covers hyaluronic acid, chitin and chitosan, starch and other natural polysaccharides. Polysaccharides have received more attention due to their numerous advantages such as their renew-ability, non-toxicity, biodegradability and ready availability. This interest has resulted in a great revolution leading to polysaccharides becoming on par with, and even superior to, synthetic materials. That is why a plethora of research studies have been undertaken to understand the potential of these natural polymers. 

Hyaluronic acid is a linear polysaccharide formed from disaccharide units containing N-acetyl-D-glucosamine and glucuronic acid. Since it is present in almost all biological fluids and tissues, hyaluronic acid-based materials are very useful in biomedical applications. After cellulose, chitin is the second most abundant natural polysaccharide resource on earth. Chitin and its de-acetylated derivative chitosan are natural polymers composed of N-acetylglucosamine and glucosamine. Both chitin and chitosan have excellent properties such as biodegradability, biocompatibility, non-toxicity, hemostatic activity and antimicrobial activity. Chitin and its derivatives are widely used in various fields of medicine. 

Another approach to improve the properties of chitosan hydrogels is via the preparation of polymer composites. Porous hydrogels of N-carboxymethyl chitosan/polyvinyl alcohol were prepared by Lee et al. [99]. Hydroxypropyl chitosan was combined with sodium alginate for the formation of biodegradable hydrogels [100]. Chitosan-hyaluronic acid composite was prepared by Tan et al. [101]. 

Tan HP, Chu CR et al (2009) Injectable in situ forming biodegradable chitosan-hyaluronic acid based hydrogels for cartilage tissue engineering. Biomaterials 30 2499-2506... 

Hyaluronic acid is a naturally occurring polysaccharide comprising monosaccharide sequences with carboxylic or acetamido side groups. Early production of hyaluronic acid, a biodegradable polymer similar to chitosan, was achieved through extraction of natural tissues, and the evolution of hyaluronic acid technology was made possible after its successful production in sufficient quantities as a fermentation product. The key evolution of... 

Hyaluronic acid Cross-linked hyaluronic acid can be used as temporary prosthesis for synovial fluid to treat arthrosis hyaluronic acid is biodegraded in the human body where it is normally regenerated. 

---