@inproceedings {15544,
	title = {Transport of small anionic and neutral solutes through chitosan membranes: Dependence on crosslinking and chelation of divalent cations},
	journal = {Tissue Engineering Part A},
	volume = {14},
	year = {2008},
	month = {2008-11-05 00:00:00},
	pages = {923-924},
	abstract = {<p style="text-align: justify;">Chitosan membranes were prepared by solvent casting and cross-linked with glutaraldehyde at several ratios<br>under homogeneous conditions. The cross-linking degree, varying from 0 to 20\%, is defined as the ratio between\&nbsp;the total aldehyde groups and the amine groups of chitosan. Permeability experiments were conducted using a\&nbsp;side-by-side diffusion cell to determine the flux of small molecules of similar size but with different chemical\&nbsp;moieties, either ionized (benzoic acid, salicylic acid, and phthalic acid) or neutral (2-phenylethanol) at physiological\&nbsp;pH. The permeability of the different model molecules revealed to be dependent on the affinity of those structurally\&nbsp;similar molecules to chitosan. The permeability of the salicylate anion was significantly enhanced by the presence\&nbsp;of metal cations commonly present in biological fluids, such as calcium and magnesium, but remained unchanged\&nbsp;for the neutral 2-phenylethanol. This effect could be explained by the chelation of metal cations on the amine\&nbsp;groups of chitosan, which increased the partition coefficient. The cross-linking degree was also correlated with\&nbsp;the permeability and partition coefficient. The change in the permeation properties of chitosan to anionic solutes\&nbsp;in the presence of these metallic cations is an important result and should be taken into consideration when trying\&nbsp;to make in vitro predictions of the drug release from chitosan-based controlled release systems.</p>},
	keywords = {chitosan membranes, crosslinking, permeability},
	author = {da Silva, R. M. P. and Caridade, S. G. and Roman, J. S. and Mano, J. F. and Reis, R. L.}
}
