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Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable safranin O delivery was observed. At acidic pH, a certain safranin O release from S1 was also found. The pH-triggered safranin O delivery was ascribed to the acid-induced hydrolysis of the carbamate moiety that linked the bulky azo derivatives onto the mesoporous inorganic magnetic support. The controlled release behavior of S1 was also tested using a model that simulated the gastro intestinal tract. [ABSTRACT FROM AUTHOR]

The present study was aimed at evaluating the possible use of inter polymer complexed (IPC) films of chitosan (CH) and carboxymethyl tamarind kernel powder (CMTKP) for colon release of budesonide. Viscosity analysis of the supernatant liquid obtained after reacting CH and CMTKP in different proportions revealed 40:60 to be the optimum stoichiometric ratio. The FTIR spectra of IPC films formed from 50:50 or 40:60 ratio of CH:CMTKP did not reveal any reduction in the peaks at 1560cm-1 and 1407cm-1 after exposure to pH 1.2, suggesting resistance of the interaction between -COO- groups of CMTKP and -NH3+ groups of CH to gastric pH. Tablets containing Avicel pH 102 as diluent and coated to a weight gain of 10%, w/w with aqueous solutions of 40:60 or 50:50 ratio of CH:CMTKP did not release budesonide in pH 1.2 buffer. Histopathology of the rat colon after oral administration of these IPC film coated tablets revealed significantly greater (p<0.05) reduction in TNBSinduced ulcerative colitis as compared to that after administration of uncoated tablets. The Cmax of budesonide achieved after oral administration of these IPC film coated tablets was comparable to that observed after administration of uncoated tablets. The results strongly indicate versatility of CH-CMTKP IPC films to deliver budesonide in the colon. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was that to synthesize macromolecular derivatives based on inulin able to complex iron and useful in the treatment of iron deficiency anaemia. Carboxylated or thiolated/carboxylated inulin derivatives were obtained by single or double step reactions, respectively. The first one was obtained by reaction of inulin (INU) with succinic anhydride (SA) alone obtaining INU–SA derivative; the second one was obtained by the reaction of INU with succinic anhydride and subsequent reaction of INU–SA with cysteine; both derivatives were treated with ferric chloride in order to obtain the INU–SA–FeIII and INU–SA–Cys–FeIII complexes. Both complexes showed an excellent biodegradability in the presence of inulinase and pronounced mucoadhesion properties; in particular, thiolated derivative INU–SA–Cys showed greater mucoadhesive properties than polyacrylic acid chosen, as a positive reference polymer, and a good iron release profile in condition mimicking the intestinal tract. These results suggest the potential employment of such systems in the oral treatment of iron deficiency anaemia or as supplement of iron in foods. [Copyright &y& Elsevier]