Mucoadhesives

Mucic acid [526-99-8] Mucoadhesives Muconic acid [505-70-4] Mucopolysaccharidoses Mucor circinelloides Mucor spp. 

A number of articles considered the association of chitosan with polylactic acid or similar compounds [47-49] another group of articles presented new data on highly cationic chitosans [ 50 - 55]. More data have also been made available on the delivery of growth factors [56] and ophthalmic drugs [57,58], on the activation of the complement, macrophages [59-61] and fibroblasts [62], on mucoadhesion [63] and functionalization of chitin [64]. The development of new carriers for the delivery of drugs, and the interactions of chitosans with living tissues seem therefore to be major topics in the current research on chitosan. Therefore, this chapter will place emphasis on these aspects. 

Mucoadhesion Involving Guar, Alginate, Carboxymethyl Cellulose,... 

Keywords Complex Flexibility Molecular weight distribution Mucoadhesion Sedimentation coefficient distribution... 

The carbohydrate has sites for ionic interaction (clusters of sialic acid or sulphate residues) and also hydrophobic interaction (clusters of hydrophobic methyl groups offered by fucose residues). Sedimentation velocity has been a valuable tool in the selection of appropriate mucoadhesives and in the characterisation of the complexes [ 138-143]. 

The approach is to first of all obtain mucin to a high degree of purity and to characterise the mucin and potential mucoadhesive. This is done by sedimentation velocity [g (s)j analysis and sedimentation equilibrium (M ) analysis—according to the procedures described above—together with SEC-MALLs [145,146]. 

Fig. 10 Sedimentation analysis of the comparative mucoadhesiveness of a chitosan (sea cure 210+, Fa 0.11) to mucins from different parts of the stomach a Mucin source b Histogram. Adapted from [151]...

Fiebrig I (1995) Solution Studies on the Mucoadhesive Potential of Various Polymers for use in Gastrointestinal Drug Delivery Systems. PhD Thesis, University of Nottingham, Nottingham, UK... 

An alternative to the oral route is the buccal mucoadhesive system. The Striant buccal system adheres to the inside of the mouth and the testosterone is absorbed through the oral mucosa and delivered to the systemic circulation. There is no first-pass effect, as the liver is bypassed by this route of administration. Patients apply a 30-mg tablet to the upper gum twice daily. The cost is similar to that of the patch or gel. Side effects unique to this dosage form include oral irritation, bitter taste, and gum edema. 

Borchard, G. LueBen, H.L. deBoer, A. G. Verhoef, J. C. Lehr, C.-M. Junginger, H.E., The potential of mucoadhesive polymers in enhancing intestinal peptide drug absorption. Ill Effects of chitosan-glutamate and carbomer on epithelial tight junctions in vitro, j. Control. Rel. 39, 131-138 (1996). 

NM Davies, SJ Farr, J Hadgraft, IW Kellaway. (1991). Evaluation of mucoadhesive polymers in ocular drug delivery. I. Viscous solutions. Pharm Res 8 1039-1043. 

MF Saettone, D Monti, MT Torracca, P Chetoni. (1994). Mucoadhesive ophthalmic vesicles Evaluation of polymeric low-viscosity formulations. J Ocular Pharmacol 10 83-92. 

CM Lehr, YH Lee, VHL Lee. (1994). Improved ocular penetration of gentamicin by mucoadhesive polymer polycarbophil in the pigmented rabbit. Invest Ophthalmol Vis Sci 35 2809-2814. 

In the gastrointestinal tract, a mucoadhesive drug delivery system provides advantages in prolonging the residence time of devices. The use of pH-sensitive bioadhesive polymers has been proposed [26], An extensive review of pH-sensi-tive hydrogels is given by Brpndsted and Kopecek [27],... 

PK Gupta, S-H Leung, JR Robinson. Bioadhesive/mucoadhesives in drug delivery to the gastrointestinal tract. In V Lenaerts, R Gurny, eds. Bioadhesive Drug Delivery Systems. Boca Raton, FL CRC Press, 1990, pp 65-92. 

Another hydrophilic polymer that has received attention is poly(vinyl alcohol) (PVA). This material holds tremendous promise as a biological drug delivery device because it is nontoxic, hydrophilic and exhibits good mucoadhesive properties (Peppas, 1987). In one of the first applications of this material, Langer and Folkman (1976) investigated the use of copolymers of PHEMA (Hydron ) and PVA as delivery vehicles for polypeptide drugs. 

The addition of PEG to the gels was critical because the PEG chains participate in the macromolecular complexes, function as a peptide stabilizer and enhance the mucoadhesive characteristics of the gels. In this work, strong dose-dependent hypoglycemic effects were observed in healthy and diabetic rats following oral administration of these gels. 

Polyanhydrides based on unsaturated and fatty acid-derived monomers are shown in Table III. Poly(fumaric acid) (PFA) was fist synthesized by Domb et al. (1991) by both melt polycondensation and solution polymerization. The copolymer of fumaric acid and sebacic acid (P(FA-SA)) has been synthesized and characterized (Domb et al., 1991 Mathiowitz et al., 1990b). The mucoadhesive properties of this polymer... 

Ceschel GC, Maffei P, Sforzini A, Lombardi Borgia S, Yasin A, Ronchi C (2002) In vitro permeation through porcine buccal mucosa of caffeic acid phenetyl ester (CAPE) from a topical mucoadhesive gel containing propolis. Fitoterapia 73 Suppl. 1 S44—S52... 

The ex vivo methods lend themselves easily for the performance of mechanistic investigations. In order to optimize selection of drug candidates prior to further clinical development, it is important to decipher the contributive roles of permeation, metabolism, efflux, and toxicity. This will then make it possible to properly channel the optimization process, for instance, by permeation enhancement, mucoadhesion, modification of the physicochemical characteristics of the drug, or even change in the route of administration in case the drug and/or formulation turns out to be too toxic. Regarding permeability studies, it is possible not only to quantify passive diffusion but also to identify and characterize (compound)-specific carrier-mediated transport routes. These tools have been used to identify and characterize the relative contribution of... 

Ugwoke MI, Verbeke N, Kinget R (2001) The biopharmaceutical aspects of nasal mucoadhesive drug delivery. J Pharm Pharmacol 53 3-21. 

Gavini E, Rassu G, Sanna V, Cossu M, Giunchedi P (2005) Mucoadhesive microspheres for nasal administration of an antiemetic drug, metoclopramide in-vitro/ex-vivo studies. J Pharm Pharmacol 57 287-294. 

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