Mucoadhesives polyethylene oxide

The periodontal pocket is another site for drug delivery in the oral cavity. Needleman et al. [46] investigated three mucoadhesive polymers (cationic chitosan, anionic xanthan gum, neutral polyethylene oxide) in vitro, using organ cultures, and in vivo in patients on their periodontal and oral mucosa. Of the polymers studied, chitosan displayed the longest adhesion in vitro and on the periodontal pockets, and the shortest adhesion on oral mucosa. 

Non-ionic polymers are less dependent on parameters such as pH levels and electrolyte concentration of the surrounding fluids. The main mechanism of mucoadhesion seems to be just physical by interpenetration and subsequent chain entanglement. Some of the polymers such as polyethylene oxide can additionally form hydrogen bonds, but still play only a minor role in macro-molecular drug delivery due to less pronounced mucoadhesive properties than the above-described charged polymers. 

Nair and Chien " compared patches and tablets of different polymers (sodium carboxymethylcellulose, car-bopol, polyethylene oxide, polymethyl vinyl ether-maleic anhydride, tragacanth) regarding their release characteristics of four drugs (chlorheximide, clotrimazole, benzo-caine, and hydrocortisone). They observed sustained release of all four compounds from the mucoadhesive tablets, but only two of the active compounds, chlorheximide and clotrimazole, could be released in a controlled manner from the mucoadhesive patches. 

Polyethylene oxide has been shown to be an excellent mucoadhesive polymer. Low levels of polyethylene oxide are effective thickeners, although alcohol is usually added to water-based formulations to provide improved viscosity stability see Table II. Polyethylene oxide films demonstrate good lubricity when wet. This property has been utilized in the development of coatings for medical devices. Polyethylene oxide can be radiation crosslinked in solution to produce a hydrogel that can be used in wound care applications. 

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