Hyaluronan system

Huntsman solvent-based collection and refining system, 15 506 Huron-Dow process, 14 42, 53 Huygens principle, 17 424 H values, 23 284 Hyaluronan, 20 577 Hyaluronic acid, 4 706 20 456 classification by structure, 4 723t function as ingredient in cosmetics, 7 829t... 

Lim, S.T., et al. 2002. In vivo evaluation of novel hyaluronan/chitosan microparticulate delivery systems for the nasal delivery of gentamicin in rabbits. Int J Pharm 231 73. 

Different drug delivery systems have been proposed for vaginal delivery of peptides and proteins. The first one was a mucoadhesive gel based on polyacrylic acid intended for vaginal administration of insulin [96]. More recently, microparticulate systems such as starch and hyaluronan ester (HYAFF) microspheres have been proposed for vaginal delivery of insulin... 

Abstract Carbohydrates have been investigated and developed as delivery vehicles for shuttling nucleic acids into cells. In this review, we present the state of the art in carbohydrate-based polymeric vehicles for nucleic acid delivery, with the focus on the recent successes in preclinical models, both in vitro and in vivo. Polymeric scaffolds based on the natural polysaccharides chitosan, hyaluronan, pullulan, dextran, and schizophyllan each have unique properties and potential for modification, and these results are discussed with the focus on facile synthetic routes and favorable performance in biological systems. Many of these carbohydrates have been used to develop alternative types of biomaterials for nucleic acid delivery to typical polyplexes, and these novel materials are discussed. Also presented are polymeric vehicles that incorporate copolymerized carbohydrates into polymer backbones based on polyethylenimine and polylysine and their effect on transfection and biocompatibility. Unique scaffolds, such as clusters and polymers based on cyclodextrin (CD), are also discussed, with the focus on recent successes in vivo and in the clinic. These results are presented with the emphasis on the role of carbohydrate and charge on transfection. Use of carbohydrates as molecular recognition ligands for cell-type specific dehvery is also briefly... 

Recently, other approaches and modifications of HA for gene delivery applications have been investigated. Among the most interesting ones are mixed chitosan-hyaluronan based gene delivery systems [68-70] and PEG-HA photocrosslinked hydrogels [71]. HA has also been used to improve the biocompatibility of branched PEI via covalent conjugation [72],... 

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],... 

During these years, our work laid the foundation for future studies on the effect of elastoviscous solutions of hyaluronan on the migration, proliferation and function of white blood cells, and how such solutions affect some functions of the immune system. We discovered that hyaluronan regulates the synthesis of glycosaminoglycans in in vitro systems, and regulates inflammation and tissue regeneration in adult animal models and tissues. All these studies laid the theoretical foundation for the therapeutic applications of hyaluronan. 

Hyaluronan is used therapeutically to treat osteoarthritis in the knee, and is an effective treatment for arthritic pain. Crosslinked hyaluronan gels are used as drug delivery systems. 

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. ... 

Older studies with radioactive precursors utilized in viuo have shown a half-life for skin hyaluronan of 2 to 5 days and for skin chondroitin sulfate of 7 to 14 days [86,87]. More recent work with cartilage indicates half-lives of approximately 7 and 50 days for large and small proteochondroitin sulfates, respectively [80]. Studies on the turnover of heparin, heparan sulfate, and dermatan sulfate indicate that degradation of the glycosaminoglycan components of these compounds in vivo occurs in mammalian systems. 

Sodium hyaluronan solutions have been advocated for the management of a variety of dry eye states, and sodium hyaluronan could be used as an additive in various drug-release systems for the eye. 

Siegelman MH, DeGrendele HC, Estess P. Activation and interaction of CD44 and hyaluronan in immunological systems. J Leukoc Biol 1999 66 315-321. 

Gianolio DA, Philbrook M, Avila LZ, MacGregor H, Duan SX, Bernasconi R, Slavsky M, Dethlefsen S, Jarrett PK, Miller RJ. Synthesis and evaluation of hydrolyzable hyaluronan-tethered bupivacaine delivery systems. Bioconjug Chem 2005 16 1512-1518. 

Moore AR, Willoughby DA. Hyaluronan as a drug delivery system for diclofenac a hypothesis for mode of action. Int J Tissue React 1995 17 153-156. Seed MP, Brown JR, Freemantle CN, Papworth JL, Colville-Nash PR, Willis D, Somerville KW, Asculai S, Willoughby DA. The inhibition of... 

Electrostatic polyelectrolyte complexes (PEC) are mentioned in the literature involving chitosan and synthetic or natural polymers such as PAA and CMC [155,156], xanthan, carrageenan, alginate [157-162], pectin [163,164], heparin, hyaluronan (HA) [165-169], sulfated cellulose, dextran sulfate, or N-acylated chitosan/chondroitin sulfate. Many systems were cited in the literature [2, 170]. The electrostatic interaction was discussed in relation with the stiffness of the backbone and the nature of the ionic groups involved. Especially, with alginate or HA, a pH-dependent complex is formed, whose stability depends on the ionic concentration. The complex formation was investigated in dilute solution by potentiometry (pH) and conductivity to determine the fraction of ion pairs (-COO + NH3 —) formed in dependence of the experimental conditions [164, 166]. 

Stem cell-scaffold systems Hyaluronan-based 3D scaffolds Mesenchymal stem cells Osteochondral repair Radice et al., 2000... 

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