Mucoadhesive preparations

The following types of mucoadhesive preparations have been evaluated for ocular drug delivery hydrogels, viscous liquids, solids (inserts), and particulate formulations [57]. Hui and Robinson [58] introduced hydrogels consisting of cross-linked polyacrylic acid for ocular delivery of progesterone in rabbits. These preparations increased progesterone concentrations in the aqueous humor four times over aqueous suspensions. 

Shojaei, A.H. and Li, X., Novel copolymers of acrylic acid and poly ethylene glycol monomethylether monomethacrylate for buccal mucoadhesion Preparation and surface characteili2Sfanri, Res.,... 

It is also possible to ensure that the mucoadhesive preparation is retained in the stomach until the active substance is dissolved completely [120] or the active substance is released from the preparation only in the colon [121]. 

For local but also systemic delivery, the oromucosal route might be suitable if safety is established. Mucoadhesive preparations, especially films, semi-solids and liquids, might be of interest if they do not interfere with suction and frequent feeding. Nevertheless, one of the major issues remains the taste of the preparation and the willingness as well as the ability of the child to retain buccal or sublingual tablets in the mouth, thus ensuring that sufficient absorption takes place. 

Hi S, Takeuchi H, Yamamoto H, Hino T, Kawashima Y. The acidic complexation of tetra-cychne with sucralfate for its mucoadhesive preparation Drug Dev IndPharm (2004) 30,715-24. 

S. Harikarnpakdee, V. Lipipun, N. Sutanthavibul, and G. C. Ritthidei. Spray-dried mucoadhesive microspheres Preparation and transport through nasal cell mono-layer. AAPS PharmSciTech 7 E12 (2006). 

All the above mentioned polymers have been evaluated mainly for application in the intestine. Finally, the last part of the gastrointestinal tract, the rectum should also be mentioned as a suitable site for delivery and fast absorption of therapeutics. Kim et al. [88] developed an in situ gelling and mucoadhesive acetaminophen liquid suppository prepared with poloxamers and sodium alginate. It was found that this particular formulation of acetaminophen in humans resulted in shorter T ax and higher maximum plasma concentrations of dmg (C ax) than the conventional acetaminophen suppositories. 

Akiyama, Y., Nagahara, N., Kashihara, T., Hirai, S., and Toguchi, H., In vitro and in vivo evaluation of mucoadhesive microspheres prepared for the gastrointestinal tract using polyglycerol esters of fatty acids and a poly(acrylic acid) derivative, Pharm. Res., 12 397-405... 

These stabilizers are added to the formulation in order to stabilize the emulsion formed during particle preparation. These stabilizers, however, can also influence the properties of the particles formed. The type and concentration of the stabilizer selected may affect the particle size. Being present at the boundary layer between the water phase and the organic phase during particle formation, the stabilizer can also be incorporated on the particle surface, modifying particle properties such as particle zeta potential and mucoadhesion (203). Other polymers have also been evaluated as stabilizers in earlier studies such as cellulosic derivatives methylcellu-lose (MC), hydroxyethylcellulose ( ), hydroxypropylcellulose (HPC), and hydroxypropylmethylcellulose (HPMC), as well as gelatin type A and B, carbomer and poloxamer (203). 

Multilamellar liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and dicetyl phosphate (DCP) were prepared by the formation of a thin lipid film and subsequent sonication, and coated with chitosan (Ch) [36], Liposomes with a size of approximately 5 pm were used in the experiment. The Ch-coated and plain liposomes were compared in terms of mucoadhesion to the rat stomach and intestinal parts. Although both the liposomes were less adhesive to the stomach, Ch-coated liposomes displayed much higher mucoadhesion to all the intestinal parts in vitro than the plain liposomes. The intestinal adhesion of the plain liposomes were minimal. Further, Ch-coated liposomes showed a great mucoadhesion to the intestine at acidic and neutral pH values. This was also confirmed by fluorescence microscopy when pyrene-loaded Ch-coated liposomes were used in the mucoadhesion test. 

Abd El-Hameeda, M.D., and I.W. Kellaway. 1997. Preparation and in vitro characterisation of mucoadhesive polymeric microspheres as intra-nasal delivery systems. Eur J Pharm Biopharm 44 53. 

Lim, S.T., et al. 2000. Preparation and evaluation of the in vitro drug release properties and mucoadhesion of novel microspheres of hyaluronic acid and chitosan. J Control Release 66 281. 

Cuna, M., Alonso, M. J., and Torres, D. Preparation and in vivo evaluation of mucoadhesive microparticles containing amoxycillin-resin complexes for drug delivery to the gastric mucosa. Eur. J. Pharm. Biopharm. 51(3) 199-205, 2001. 

Bernkop-Schniirch, A., Weithaler, A., Albrecht, K., and Greimel, A. Thiomers preparation and in vitro evaluation of a mucoadhesive nanoparticulate drug delivery system. Int. J. Pharm. 2006 317, 1,76-81. 

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. 

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