Chitosan-coated liposomes

Another trend observed during the past decade was the coating of liposomes with mucoadhesive polymers. Liposomes are coated with chitosan, long-ehain polyvinyl alcohol, and polyacrylates bearing a cholesteryl group [90]. Chitosan-eoated liposomes showed superior adhesion properties to rat intestine in vitro than the other polymer-eoated liposomes. In vivo, chitosan-coated liposomes containing insulin substantially reduced blood glueose levels after oral administration in rats, whieh were sustained up to 12 hr after administration [90]. 

Takeuchi, H., Yamamoto, H., Niwa, T., Hino, T., and Kawashima, Y., Enteral absorption of insulin in rats from mucoadhesive chitosan-coated liposomes, Pharm. Res., 13 896-901 (1996). 

Filipovic-Grcic, J., Skalko-Basnet, N., and Jalsenjak, I. (2001). Mucoadhesive chitosan-coated liposomes Characteristics and stability. ]. Microencapsul. 18, 3-12. 

Chitosan-Coated Liposomes Containing Peptide Drugs.61... 

FIGURE 3.2 Blood glucose concentration-time profiles in normal rats after oral administration of insulin-containing chitosan-coated liposomes, insulin-containing plain liposomes and insulin solution, and subcutaneous administration of insulin solution. Sol, solution Lip, liposomes Ch, chitosan s.c., subcutaneous. The results are expressed as the mean values. 

These polymer-coated liposomes showed high potency in oral delivery of peptide drugs such as insulin and calcitonin, mainly because of the mucoadhe-sion of the chitosan-coated liposomes to the intestinal tract (Takeuchi et al. 1996, 2001,2003,2005a). Similar trials have been reported by Guo et al. (2003), who investigated the effect of chitosan concentration and lipid type on the characteristics of chitosan-coated liposomes and their interactions with leupro-lide. They found that a thicker adsorptive layer could be realized by using low... 

In order to observe the behavior of chitosan-coated liposomes more precisely, chitosan was labeled with fluorescein isothiocyanate (FITC) via chemical reaction at the isothiocyanate group of FITC and the primary amino group of chitosan the liposomes (Lips) were marked by incorporation of Dil into the liposomal formulation. FITC-labeled chitosan (FITC-CS), non-coated liposomes, and FITC-labeled chitosan-coated liposomes (FITC-CS-Lips) were intragastrically administered into male Wistar rats, and then the behavior of the molecules was visualized by CLSM (Thongborisute et al. 2006a). The results demonstrated that the chitosan molecules themselves, as well as the liposomes, could penetrate across the intestinal mucosa. Moreover, the CLSM images demonstrated a lack of separation of the chitosan molecules from the surface of the liposomes after the administration of chitosan-coated liposomes. 

Sriamornsak P, Thirawong N, Nunthanid J, Puttipipatkhachorn S, Thongborisute J, Takeu-chi H (2008) Atomic force microscopy imaging of novel self-assembling pectin-liposome nanocomplexes. Carbohydr Polym 71 (2) 324—329 Takeuchi H, Yamamoto H, Niwa T, Hino T, Kawashima Y (1994) Mucoadhesion of polymer-coated liposomes to rat intestine in vitro. Chem Pharm Bull 42(9) 1954-1956 Takeuchi H, Yamamoto H, Niwa K, Hino T, Kawashima Y (1996) Enteral absorption of insulin in rats from mucoadhesive chitosan-coated liposomes. Pharm Res 13 896-901 Takeuchi H, Kojima H, Yamamoto H, Kawashima Y (2000) Polymer coating of liposomes with a modified polyvinyl alcohol and their systemic circulation and RES uptake in rats. J Control Rel 68(2) 195-205... 

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... 

Thongborisute J, Tsuruta A, Kawabata Y, Takeuchi H (2006c) The effect of particle structure of chitosan-coated liposomes and type of chitosan on oral delivery of calcitonin. J Drug Target 14(3) 147-154... 

Thongborisute J, Tsuruta A, Takeuchi H (2008) Correlation of drug absorption level and pharmacological efficiency of oral chitosan-coated liposomal systems. Unpublished Torres-Lugo M, Garcia M, Record R, Peppas NA (2002) Physicochemical behavior and cytotoxic effects of p(methacrylic acid-g-ethylene glycol) nanospheres for oral delivery of proteins. J Control Rel 80(1-3) 197-205... 

Yamamoto H, Takeuchi H, Hino T, et al. (2000). Mucoadhesive liposomes Physicochemical properties and release behavior of water-soluble drugs from chitosan-coated liposomes. S.T.P. Pharma. Sci. 10 63-68. 

Low-molecular-weight chitosan-coated liposomes (LCHLs) designed by the drug cyclosporine A (CsA) can be encapsnlated as a model drug inside LCHL. " ... 

Zaru, M. Manca, M.L. Eadda, A.M. Antimisiaris, S.G. Chitosan-coated liposomes for delivery to lungs by nebulization. Colloids Surf. B Biointerfaces 2009, 71 (1), 88-95. 

FIGURE 25.7 Fluorescence micrographs of the nasal tissue of rats excised following administration of (A) FITC-BSA solution (B) FITC-BSA encapsulated in plain liposomes or (C) FITC-BSA encapsulated in glycol chitosan coated liposomes. (From Khatri, K. et ah, Vaccine, 26, 2225, 2008. With permission.)... 

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