Acrylic acid delivery systems

Solubilization of vinylpyrrolidone, acrylic acid, and A,A -methylene-bis-acrylamide in AOT-reversed micelles allowed the synthesis in situ of a cross-linked polymer with narrow size distribution confined in the micellar domain. These particles displayed high entrapment efficiency of small hydrophilic drugs and have been considered interesting drug delivery systems [239],... 

An interesting feature of current commercial products is that the polymer vehicles available for formulation have been limited to nonionic and anionic materials. The delivery vehicles available included off-the-shelf polymers such as carboxymethylcellulose, soluble starch, hydroxyethyl-cellulose, polyvinyl alcohol, poly(acrylic acid), and polyvinylpyrrolidone, or mixtures thereof. The choice of available polymeric delivery system primarily depends on component compatibility, aesthetics, and efficacy. However, by reliance upon available (off-the-shelf) systems, limitations on bioadhesion, drug bioavailability, contraceptive efficacy, and end-use characteristics has been limited. 

The failure in increasing residence time of mucoadhesive systems in the human intestinal tract has led scientists to the evaluation of multifunctional mucoadhesive polymers. Research in the area of mucoadhesive drug delivery systems has shed light on other properties of some of the mucoadhesive polymers. One important class of mucoadhesive polymers, poly(acrylic acid) derivatives, has been identified as potent inhibitors of proteolytic enzymes [72-74]. The interaction between various types of mucoadhesive polymers and epithelial cells has a direct influence on the permeability of mucosal epithelia by means of changing the gating properties of the tight jrmctions. More than being only adhesives, some mucoadhesive polymers can therefore be considered as a novel class of multifunctional macromolecules with a number of desirable properties for their use as delivery adjuvants [72,75]. 

A host of bioadhesive controlled release systems have been proposed in recent years. Among the most commonly studied applications of bioadhesive materials is the area of buccal controlled delivery [408], The buccal delivery of small peptides from bioadhesive polymers was studied by Bodde and coworkers [409], and a wide range of compositions based on poly(butyl acrylate) and/or poly(acrylic acid) gave satisfactory performance. Bioadhesive poly(acrylic add)-based formulations have also been used for oral applications [402,410] for the sustained delivery of chlorothiazide [410] and for a thin bioadhesive patch for treatment of gingivitis and periodontal disease [411]. Other bioadhesive applications of polyelectrolytes include materials for ophthalmic vehicles [412,413], and systems for oral [410,414,415-419], rectal [420,421] vaginal [422] and nasal [423] drug delivery. 

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Another area in which smart hydrogels are likely to find application is the development of more efficient drug delivery systems. One material that has showed promise in this held is called Pluronic-PAA. Its trade name is Smart Hydrogel . The material is a mixture of two polymers, one of which is poly(acrylic acid) (PAA), which attaches readily to other biological materials and is responsive to changes in pH. The other polymer is a copolymer of poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO). This copolymer belongs to a family of polymers known by the trade name of Pluronic polymers. 

The first nanoparticulate delivery system studied was Piloplex, consisting of pilocarpine ionically bound to poly(methyl)methacrylate-acrylic acid copolymer nanoparticles [44], Klein et al. [1,98] found that a twice-daily application of Piloplex in glaucoma patients was just as effective as three to six instillations of conventional pilocarpine eye drops. However, the formulation was never accepted for commercialization due to various formulation-related problems, including the nonbiodegradability, local toxicity, and difficulty of preparing a sterile formulation [208],... 

Gelatin-poly(acrylic acid) In rats Slow-release drug delivery system with good adhesive characteristics 89... 

In another investigation by the author [1], poly(acrylic acid)-g-poly(lactic acid), (1), was prepared and used as a bioadhesive conjugated with biodegradable components in drug delivery systems. 

Cyanoacrylate (Histoacryl) is a tissue adhesive used in duraplasty. The sites at which it is used should be carefully chosen. Cyanoacrylates are also in use for embolization of arteriovenous malformations in the brain. The risk of this procedure is the creation of pulmonary emboli after acrylate glue injection, particularly when delivery systems without flow arrest are used in high-flow vascular brain lesions. Techniques using acetic acid to delay polymerization time and sandwich techniques, in which glue is pushed with dextrose, appear to be more likely to cause this complication (1). 

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