Polymer-coated liposomes

Takeuchi, H., Yamamoto, H., Niwa, T., Hino, T., and Kawashima, Y. Mucoadhesion of polymer-coated liposomes to rat intestine in vitro. Chem. Pharm. Bull. (Tokyo) 1994 42, 9, 1954-1956. 

In this chapter, the preparation methods and efficacy of novel lipid particles such as polymer-coated liposomes and polymer-liposome complexes for peptide drug delivery are described. Both systems have common characteristics of mucoadhesion. 

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 designing polymer-coated liposomes containing peptide drugs, attention should also be paid to their structure. Drugs can be loaded into a liposomal... 

Takeuchi et al. (1996) have confirmed the mucoadhesive properties of polymer-coated liposomes with a simple particle counting method in vitro. This mucoadhe-sion test was carried out using intestines isolated from male Wistar rats. The intestines were washed with saline solution, filled with a liposomal suspension that was diluted 100-fold with a buffer solution (pH 7.4, 6.5, 5.6 or 1.2) or saline... 

Fig. 10.4 Adhesive% of polymer-coated liposomes in rat intestine (taken from Takeuchi et al. 1996). Lipid composition DPPC DCP=8 2. Dispersion medium phosphate buffer solution...

Fig. 10.5 Protocol for measurement of the mucoadhesive behavior of polymer-coated liposomes with confocal laser scanning microscopy (CLSM)...

The mucoadhesion of the liposome-based formulations was examined both in vitro and in vivo. Using CLSM, the penetration of polymer-coated liposomes or polymer-liposome complexes into a layer of mucus in the rats after oral administration was confirmed. The pharmacological action of the model peptide drugs... 

Nagata T, Tozuka Y, Takeuchi H (2006) Design and evaluation of polymer-coated liposomes for mucosal absorption of drugs. Proceedings of the 23th symposium on particulate preparation and designs 23 168-171... 

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... 

Another trend observed during the past decade was the coating of liposomes with mucoadhesive polymers. Liposomes are coated with chitosan, long-chain PVA, and polyacrylates bearing a cholesteryl group. Chitosan-coated liposomes showed superior adhesion properties to rat intestine in vitro than the other polymer-coated liposomes. In vivo, chitosan-coated liposomes containing insulin substantially reduced blood glucose levels after oral administration in rats, which were sustained up to 12 h after administration. ... 

Torchulin VP, Omelyanenko VG, Papisov MI, Bogdanov AAJ, Trubetskoy VS, Herron JN, Gentry CA (1994) Poly(ethylene glycol) on the liposomes siorface on the mechanism of polymer-coated liposome longevity. Biochim Biophys Acta 1195 11-20... 

Ozden MY, Hasirci VN (1990) Enzyme immobilization in polymer coated liposomes. Brit Polym J 23(3) 229-234... 

Thermosensitive HPMA mono/dilactate polymer was prepared and the temperature-triggered release of content from polymer-coated liposomes studied. HPMA mono/ dilactate polymer was synthesized with a cholesterol anchor suitable for incorporation in the liposomal bilayers and with a cloud point temperature of the polymer slightly above normal body temperature (42°C)... 

Some liposomes were applied by injections and were modified with polymers attached to the surface of the lipid bilayer. These modifications were made in order to prevent macrophage-mediated endocytosis of the endothelial reticle, which causes increase in the probability of reaching the site of action [66], Polymer-coated liposomes offer new mucoadhesive properties, a longer permanence time to obtain higher bioavailability [95],... 

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