Mucoadhesive propertie chitosan

Chitosan, produced commercially by deacetylation of chitin, is a natural polysaccharide composed of randomly distributed (J-l, 4-linked D-glucosamine and N-acetyl-a-glucosamine. Because of its nontoxic, biocompatible, biodegradable and mucoadhesive properties, chitosan is widely used in the pharmaceutical field [171]. Chitosan has been used as a carrier system for hormones [172], proteins [173], enzymes [174], and genes [175]. Because of its apparent pKa = 5.6 [176], the application of chitosan in the oral administration of protein and peptide drugs is restricted by its easy dissolution in a low pH environment. 

The oral administration of peptidic drugs requires their protection from degradation in the gastric environment and the improvement of their absorption in the intestinal tract. In general, the barriers can be divided into the absorption and the enzymatic barrier, which are mainly responsible for a very low bioavailability of orally given peptides and proteins. Because of i) their permeation enhancing effect, ii) enzyme inhibitory capabilities, and iii) mucoadhesive properties, chitosan and... 

The mucoadhesive properties of several classes of hydrogels have been identified, and two types of polymers have attracted special attention. Polyacrylates and their cross-linked modifications represent the anionic type, chitosan and its derivatives the cationic group. In addition, both types of polymers show a number of interesting characteristics beneficial for the administration of a wide range of therapeutics. 

Lehr, C.M., et al. n vitro evaluation of mucoadhesive properties of chitosan and some other natural polymers,Int. J. Pharm., 78, 43, 1992. 

Chitosan not only displays mucoadhesive properties, but also acts as an absorption enhancer in the intestinal cell layer membrane [34,35]. The mucoadhesion raises the concentration of... 

Some of the most promising data on gastroretentive delivery systems using bioadhesion have resulted from the use of acrylate-based as well as chitosan-based polymers. Poly(acrylates) have been shown to have significant mucoadhesive properties in contact with intestinal mucosal tissues.104 122 135 Longer et al.136 demonstrated successful reduction in the... 

Takeuchi, H., Matsui, Y., Yamamoto, H., and Kawashima, Y. Mucoadhesive properties of carbopol or chitosan-coated liposomes and their effectiveness in the oral administration of calcitonin to rats. J. Contr. Rel. 86 235—242, 2003. 

Snyman, D., Hamman, J.H. and Kotze, A.F. (2003) Evaluation of the mucoadhesive properties of /V-trimethyl chitosan chloride. Drug Dev. Ind. Pharm. 29 59-67. 

Fig. 8.3 Mucoadhesive properties of polycarbophil-cysteine (PCP Cys) and chitosan-thioglycolic acid (TGA) in comparison to unmodified control (Bernkop-Schnurch et al. 1999 Kast and Bernkop-Schnurch 2001)...

Takeuchi H, Yamamoto H, Kawashima Y (2001) Mucoadhesive nanoparticulate systems for peptide drug delivery. Adv Drug Del Rev 47( 1 ) 39—54 Takeuchi H, Matsui Y, Yamamoto H, Kawashima Y (2003) Mucoadhesive properties of carbopol or chitosan-coated liposomes and their effectiveness in the oral administration of calcitonin to rats. J Control Rel 86(2-3) 235-242 Takeuchi H, Matsui Y, Sugihara H, Yamamoto H, Kawashima Y (2005a) Effectiveness of submicron-sized, chitosan-coated liposomes in oral administration of peptide drugs. Int J Pharm 303(1-2) 160-170... 

Thongborisute J, Takeuchi H, Yamamoto H, Kawashima Y (2006a) Visualization of the penetrative and mucoadhesive properties of chitosan and chitosan-coated liposomes through the rat intestine. J Liposome Res 16(2) 127-141 Thongborisute J, Takeuchi H, Yamamoto H, Kawashima Y (2006b) Properties of liposomes coated with hydrophobically modified chitosan in oral liposomal drug dehvery. Pharmazie 61 (2) 106—111... 

Chitosan An amino polysaccharide made by deacetylation of chitin. Its mucoadhesive properties make it ideal for oral and nasal administration (71-73)... 

Chitosan, hyaluronan, In vitro Prolonged release, improved mucoadhesive properties 51... 

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