title: Study of the release mechanism of diltiazem hydrochloride from matrices based on chitosan-alginate and chitosan-carrageenan mixtures.
abstract: The aim of this work was to establish the diltiazem hydrochloride release mechanism from the chitosan-alginate matrix tablet (MCB/AS) and chitosan-carrageenan matrix tablet (MCS/CSI). The weight loss for MCS/CSI is mainly due to the weight loss of the matrix while for MCB/AS it is mainly due to the diltiazem hydrochloride released from the tablet. Using the Peppa's model the release order for MCS/CSI was n = 1.07 +/- 0.13 and for MCB/AS was n = 0.76 +/- 0.02. Thus, MCS/CSI has a transport mechanism, and for MCB/AS the drug release mechanism is a combined process of diffusion and relaxation. MCB/AS has an elastic modulus (G' = 10(5) Pa) one order of magnitude higher than MCS/CSI (G' = 10(4) Pa). MCB/AS is able to uptake solvent without disrupting the microstructure due to its high elastic modulus. Instead MCS/CSI showed a quick erosion process, which conducted to the tablet disintegration due to a fast solvent uptake process.
authors.affiliation: Laboratory of Unit Operations, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Casilla 233, Santiago 1, Chile. ctapia@uchile.cl
authors.forename: C
authors.initials: C
authors.lastname: Tapia
authors.forename: V
authors.initials: V
authors.lastname: Corbalán
authors.forename: E
authors.initials: E
authors.lastname: Costa
authors.forename: M N
authors.initials: MN
authors.lastname: Gai
authors.forename: M
authors.initials: M
authors.lastname: Yazdani-Pedram
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000959:Antihypertensive Agents / Q000493:pharmacokinetics*; D001672:Biocompatible Materials / Q000737:chemistry; D002351:Carrageenan / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004110:Diltiazem / Q000493:pharmacokinetics*; D016503:Drug Delivery Systems; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D020100:Hydrogels; D007700:Kinetics; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013607:Tablets; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000464:Alginates; D000959:Antihypertensive Agents; D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D006603:Hexuronic Acids; D020100:Hydrogels; D012997:Solvents; D013607:Tablets; D014867:Water; D020723:Glucuronic Acid; D002351:Carrageenan; D048271:Chitosan; D004110:Diltiazem