Poly derivatives, mucoadhesive

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... 

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]. 

Akiyama, Y., Nagahara, N., Kashihara, T., Hirai, S., and Toguchi, H., In vitro and in vivo evaluation of mucoadhesive microspheres prepared for the gastrointestinal tract using polyglycerol esters of fatty acids and a poly(acrylic acid) derivative, Pharm. Res., 12 397-405... 

However, according to Park and Robinson [193], poly anions are better than polycations in terms of binding and potential toxicity. In general, both anionic and cationic charged polymers demonstrate better mucoadhesive properties than nonionic polymer, such as cellulose derivates or PVA [194,195],... 

Finally, it should be noted that during the last decade both weakly crosslinked poly(acrylic acid) derivatives and chitosan derivatives were described as safe penetration enhancers for hydrophilic compounds especially as they can trigger mechanisms of tight junction opening of mucosal tissues and did not show acute toxicity. Poly(acrylic acid) derivatives were shown to have excellent mucoadhesive properties and can inhibit the activity of gut enzymes, such as trypsin, chymo-trypsin, and carboxypepsidases. Chitosan salts and Ni-trimethylchitosan chloride revealed to be potential absorption enhancers for nasal absorption of calcitonin and insulin and for the intestinal absorption of buserilin.f ... 

Poly(acrylic acid) (PAA) (Figure 16.5) is an anionic mucoadhesive polymer produced by the radical polymerization of acrylic add. PAA and its derivatives—weakly crosslinked PAAs, also known as Carbomers or Carbopol—are widely used in ophthalmic formulation, such as the ones used for the management of the dry eye condition. Generally, PAA and its derivatives are used in the preparation of mucoadhesive ocular drug delivery formulations [25], either in the form of viscous gels [26], nanoparticles... 

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