Polymeric Films and Hydrogels

Polymeric films based on maleic copolymers are used for enteric, ocular, and trans-dermal drug delivery (Table 10.5) because they were proved to be bioadhesive and mucoadhesive [151-153], Loaded films can be prepared by dissolving the drug and the copolymer in anhydride form in organic solvents (acetone-water mixture, isopropanol, 2-butanol) and casting [139,154-159]. Water can also be a solvent for the formation of the films/hydrogels, but in this case the hydrolysis of the maleic copolymer takes place before the contact with the body [151-153,160-162]. [Pg.293]

The dissolution of the polymer and the release rate increase with the pH of the medium. This pH sensitivity could be used to modify the drug release rate by incorporating it in the polymer matrix basic salts [156], which raise the pH at the interface, or urease [155], which in the presence of external urea increases the pH and accelerates polymer erosion. [Pg.293]

When the films based on MA-MVE are plasticized with polysorbates (Tween 20, Tween 80), or with glycerol, chemical crosslinking can occur through esterification of maleic anhydride groups with hydroxyl groups of the plasticizer. Thus, the films progressively lose their water solubility and their adhesion on storage [154,160,163]. If [Pg.293]

MA-MVE esters with alcohols with different chain length hydrocortisone (treatment of eczema and dermatitis) 139, 155 [Pg.293]

MA-MVE isopropyl ester timolol (ophthalmic use, reduced high blood pressure) 156 [Pg.293]

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