title: Cross-linked chondroitin sulphate: characterization for drug delivery purposes.
abstract: Chondroitin sulphate was cross-linked with 1,12-diaminododecane to give a series of cross-linked products with reduced water solubility. Since the water solubility of the modified polymers is low, their chemical characterization is complicated. A new method based on the adsorption of the cationic dye, methylene blue, on the cross-linked polymers was developed to characterize the degree of cross-linking. It was found that the values of the adsorptive capacity of the adsorbate, Cp(s), decreased with the extent of cross-linking. However, the valves of the absorptive coefficient. K, and the free energy change of the absorption reaction, delta mu degrees, increased with cross-linking. The swelling of films made of the cross-linked polymers was measured in water and an exponential-like dependency between the degree of swelling and extent of cross-linking could be defined. Indomethacin tablets made of two types of cross-linked polymers--very low water soluble and relatively high water soluble--were made and analysed for their water uptake and drug release characteristics. Based on the physicochemical properties, an optimal product with a potential to serve as a colon-specific drug carrier was suggested.
authors.affiliation: Perio Products Ltd, Jerusalem, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Sintov
authors.forename: N
authors.initials: N
authors.lastname: Di-Capua
authors.forename: A
authors.initials: A
authors.lastname: Rubinstein
mesh_terms: D000327:Adsorption; D002809:Chondroitin Sulfates / Q000737:chemistry / Q000378:metabolism*; D003106:Colon / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000378:metabolism; D003956:Dialysis; D003959:Diamines / Q000737:chemistry; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000008:administration & dosage*; D008751:Methylene Blue / Q000737:chemistry / Q000378:metabolism; D012995:Solubility; D013056:Spectrophotometry, Ultraviolet; D013607:Tablets; D013816:Thermodynamics
chemical_list: D003432:Cross-Linking Reagents; D003959:Diamines; D013607:Tablets; C016417:1,12-dodecamethylenediamine; D002809:Chondroitin Sulfates; D008751:Methylene Blue; D007213:Indomethacin