Hyaluronan preparations

Ohshima Y, Yokota S, Kasama K, Ono H. Comparative studies on levels of proteins, bacterial endotoxins and nucleic acids in hyaluronan preparations used to treat osteoarthritis of the knee—could residual proteins and bacterial endotoxins relate to complications. Jpn Pharmacol Ther 2004 32 655-662. 

Maheu E, Ayral X, Dougados M. A hyaluronan preparation (500- 730 kDa) in the treatment of osteoarthritis a review of clinical trials with HyalganfR). IntJ Clin Pract 2002 56 804-813. 

Lapcik, L. Jr., Lapcik, L., De Smedt, S., Demees-ter, J., and Chabrecek, P. (1998). Hyaluronan preparation, structure, properties, and applications. Chemical Review 98,2663-2684. 

We prepared a phenol-containing hyaluronan derivative, which was inter-molecularly coupled by HRP to yield a crosslinked hydrogel (Scheme 27). The sequenhal injection of this hyaluronan derivative and peroxidase formed... 

Four intraarticular hyaluronic acid preparations are available for treating pain associated with OA of the knee sodium hyaluronate (Hyalgan 20 mg/2 ml Supartz 25 mg/2.5 mL), hylan polymers (Synvisc 16 mg/2 mL), and hyaluronan (Orthovisc 30 mg/2 mL). Hyalgan and Supartz are administered once weekly for five injections, whereas Synvisc and Orthovisc are administered once weekly for three injections. 

One such application could be delivery of Has2-pDNA, a plasmid that codes for hyaluronan synthase 2 [66]. This enzyme facilitates the synthesis of larger HA molecules and can prevent post-surgical peritoneal adhesions. In one study, DNA-HA films were prepared using previously-described chemistry however, lyophili-zation was replaced with air-drying under sterile conditions and an isopropanol/ H20 mixture was used instead of DMF/H20. The release kinetics of DNA were similar to that from the HA film described previously, but release did not occur until after 7 days. The reason for this delay was not completely clear the authors suggest that a possible way to overcome the delay is to use a crosslinked DNA-HA film sandwiched between two non-crosslinked DNA-HA films. Non-crosslinked film... 

The physical or chemical crosslinking of polymers can be also realized in water-in-oil (W/O) emulsion systems. In this case, aqueous droplets of prepolymers are stabilized by oil-soluble surfactants in a continuous oil phase. Hyaluronan-based microgels were prepared by crosslinking of carboxylic units of hyaluronan with adipic dihydrazide in aqueous droplets [19]. Chitosan-based microgels were prepared by crosslinking of chitosan chains with glutaraldehyde in aqueous droplets [20-25],... 

The typical biopolymers used for the preparation of micro- and nanogels are polysaccharides (Scheme 11) cellulose (CL), chitosan (CS), hyaluronan (HA), heparin, pullulan (PuL), dextran, and gelatin - a proteinaceous polyamolytic gel obtained by partial hydrolysis of collagen. Gelatine microgels are addressed by Landfester and Musyanovych in another chapter of this issue [5] and will thus not be discussed further here. 

The Laurents became very important in my life and in the life of the hyaluronan molecule. Torvard s doctoral thesis for which I was in part his advisor, was on the physical chemistry of hyaluronan, and contained some of our early work together. He and Ulla, who also made her doctoral thesis on hyaluronan, continued to do research on this molecule for decades to come. Torvard became one of the youngest professors and head of the Department of Medical Chemistry in Uppsala and concentrated his own work and that of most of his doctoral students on research on hyaluronan and other molecules of the intercellular matrix. Several young Swedish physicians worked for years in my laboratory on vitreus and cornea of the eye in preparing their doctoral thesis. 

Ghezzo E, Beredetti LM, Rochira M, et al. Hyaluronan derivative microspheres as NGF delivery devices preparation methods and in vitro release characterization. Int ] Pharm 1992 29 133-141. 

Microspheres prepared from hyaluronan esters have been evaluated for the vaginal administration of calcitonin in the treatment of postmenopausal osteoporosis. Microspheres prepared from hyaluronan esters have also been used experimentally as delivery devices for nerve growth factors, and as a nasal delivery system for insulin. ... 

Commercial preparations usually contain this type of hyaluronidase. The enzyme is found in testicular tissue of most mammals and is located in the acrosomal cap of spermatozoa [6], Testicular hyaluronidase degrades hyaluronan, chondroitin, chondroitin-4- and -6-sulfate to oligosaccharides, mainly tetrasaccharides [1]. Partial degradation of dermatan sulfate has been described [7]. Testicular hyaluronidase had a broad pH range of activity [5]. 

The European Pharmacopoeia and HP standard viscosimetric method is described in Chapter IS. In the proposed method, both hyaluronidase and hyaluronan are available as well-defined stable standard preparations, eliminating variations in test results due to the absence of a well-defined substrate. With slight modifications the method can be used for the determination of hyaluronidase in serum [137]. 

Eva Hrabarova works at the Institute of Chemistry, Slovak Academy of Sciences in Bratislava, Slovakia. Her research interests focus on the study of preparation of cellulose derivatives, characterization of pectins/pectates, hyaluronan degradation, isolation and characterization of recombinant proteins such as GFP. 

Hariraksapitak and Supaphol [45] prepared functional bone scaffolds capable of enhanced physical, mechanical, and biological performances. The materials used to fabricate the porous scaffolds were hyaluronan and gelatin (1 1 w/w blend), and the reinforcing filler was nanochitin obtained from acid-hydrolyzed a-chitin. 

In another study Feng et al. [86] presented the stmcture and properties of new thermoforming bionanocomposites based on chitin whiskers-graft-polycaprolac-tone. The synthesized material was characterized by FTIR, SEM, TEM and XRD. The surface and mechanical properties were also determined and discussed. Ha-riraksapitak et al. [87] prepared a neat hyaluronan-gelatin scaffolds and chitin-whisker-reinforced hyaluronan-gelatin scaffolds. The obtained cylindrical scaffolds obtained were about 10 mm in diameter and 2 mm in height, whereas the disc-shaped scaffolds were about 1 mm in thickness these were later cut into a desired shape and size for the mechanical property assessment. 

Most of the recent reported polymer/CW nanocomposites were prepared by this method. The reported polymer matrixes contain poly(styrene-co-butyl acrylate) [36], poly(caprolactone) [37], natural rubber [39,140,141], soy protein isolate [38], poly(vinyl alcohol) [42, 44], chitosan [41, 141], silk fibroin, [142], alginate [44], starch [143], hyaluronan-gelatin [55], and waterborne polyurethane [144, 145]. 

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