Bioadhesion of polymers

Jacob, J., Santos, C., Carino, G., et al. An in-vitro bioassay for quantification of bioadhesion of polymer microspheres to mucosal epithelium. Proceed. Int. Symp. Control. Rel. Bioact. Mater. 22 312—313, 1995. 

Mikos and Peppas described the flow channel to measure the bioadhesion of polymer microparticles on mucin gels. Later Lehr et al. ° used an in situ loop model in the rat for the investigation of mucoadhesive microspheres (Fig. 3). They concluded that this approach allowed the study of the transit of particles. Another technique to study the mucoadhesive properties of microspheres is the electrobalance method, as... 

Table II. Examples of Polymers with Bioadhesive Properties...

Matthew V. Tirrell (Co-Chair) is Dean of the College of Engineering at the University of California at Santa Barbara. He was previously Professor and Head of the Department of Chemical Engineering and Materials Science at the University of Minnesota, where he served as Director of its Biomedical Engineering Institute. He received a B.S. from Northwestern University and a Ph.D. from University of Massachusetts. His interests are in transport and interfacial properties of polymers, with particular emphasis on molecular-scale mechanical measurements, bioadhesion, and new materials development. He is a member of the National Academy of Engineering. 

Interpenetration of the bioadhesive polymer chains and entanglement of polymer and muein ehains, and... 

The diffusion theory states that interpenetration and entanglement of polymer chains are additionally responsible for bioadhesion. The intimate contact of the two substrates is essential for diffusion to occur, that is, the driving force for the interdiffusion is the concentration gradient across the interface. The penetration of polymer chains into the mucus network, and vice versa, is dependent on concentration gradients and diffusion coefficients. It is believed that for an effective adhesion bond the interpenetration of the polymer chain should be in the range of 0.2-0.5 pm. It is possible to estimate the penetration depth (/) by Eq. (5),... 

Peppas, N.A., and Buri, P., Surface, interfacial and molecular aspects of polymer bioadhesion on soft tissue, J. Control. Rel., 2 257-275 (1985). 

Caramella, C M., Rossi, S., and Bonferoni, M.C., A Rheological Approach to Explain the Mucoadhesive Behavior of Polymer Hydrogels. In Bioadhesive Drug Delivery Systems (E. Mathiowitz, D.E. Chickering, III, and C.-M. Lehr, eds.), Marcel Dekker, Inc., New York, 1999, pp. 25-65. 

A variety of polymers including water-soluble and insoluble, ionic and nonionic hydrocolloids, and water-insoluble hydrogels can be used in bioadhesive systems [31]. The bioadhesive properties of the polymer are affected by the ... 

A variety of water-soluble and water-insoluble polymers of both synthetic and natural origin [31] have been studied as bioadhesives. These polymers are used mainly to... 

For bioadhesive applications, anionic polymers appear to provide the most effective balance between adhesiveness and toxicity, with carboxylic materials preferred over sulfonic polymers [400]. Polyfacrylic acid) microparticles have been identified as particularly effective bioadhesive materials [402]. Studies with poly(acrylic acid) microparticles have indicated that, while water-swollen particles exhibit good bioadhesion, dry polymer particles give no adhesion at all. In addition, adhesive strength increases as the degree of ionization of the polymer is increased [402]. Thus the expanded nature of the polymer network is important to mucoadhesion, probably via polymer interdiffusion and entanglement with mucin [403],... 

Bioadhesive tablets can be made by the compression of polymers or can consist of a matrix base or bilayers, with an impermeable backing layer covering the layer with the drug and the mucoadhesion polymer. Examples of these systems are discussed below. 

Baloglu, E., et al. 2003. An in vitro investigation for vaginal bioadhesive formulations Bioadhesive properties and swelling states of polymer mixtures. Farmaco 58 391. 

Bernkop-Schnurch A, Humenberger C, Yalenta C (1998) Basic studies on bioadhesive delivery systems for peptide and protein drugs. Int J Pharm 165(2) 217-225 Chae SY, Jang M-K, Nah J-W (2005) Influence of molecular weight on oral absorption of water soluble chitosans. J Control Rel 102(2) 383-394 Cho EC, Lim HJ, Shim J, Park JY, Dan N, Kim J, Chang I-S (2007) Effect of polymer characteristics on structure of polymer-liposome complexes. J Colloid Interf Sci 311(1) 243-252... 

The principal mechanism for bioadhesion of oral patches appears to be physical entanglement of the adhesive polymer of the patch in the mucus glycoprotein chains, with secondary (electrostatic, hydrogen, hydrophobic) chemical bonding playing a minor role. 

The diffusion theory states that interpenetration and entanglement of polymer chains are additionally responsible for bioadhesion. The intimate contact of the two substrates is essential for diffusion to occur that is, the driving force for the interdiffusion is the... 

Polycarbophil, poly(acrylic acid) polymers crosslinked with divinyl glycol, is available for bioadhesive or medicinal applications. Carbomers designated with the letter P , e.g. carbomer 971P, are the only pharmaceutical grades of polymer accepted for oral or mucosal contact products. These resins are particularly useful in the production of clear gels. 

Bioadhesivity of water-soluble polymers 8.4.9 Polymers as wound dressings... 

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