title: Enzymatic erosion of bioartificial membranes to control drug delivery.
abstract: The preparation of an enzymatic controlled drug release system from blends of PVA/starch/alphaA, in the form of films, is described. It was shown that alphaA hydrolyses the starch within these films, resulting in a time-dependent change of the porosity in the matrix. Films were characterized by calorimetric analysis to study the interactions between the enzyme and the polymeric constituents at the molecular level. The presence of alphaA, in fact, influenced the PVA crystallization in the blends. Release tests and permeability experiments were carried out to evaluate the transport properties of the films. An increase in porosity and permeability was observed by increasing alphaA content (16-28 wt.-%). Films loaded with theophylline and caffeine were also prepared to analyze drug release properties of the matrix. Drug release kinetics were coherent with the measured changes in porosity: at higher alphaA concentrations the amount of released drug increased under the influence of diffusion and erosion processes. The results obtained are promising for the realization of drug delivery devices for a rapid release or for the release of poorly soluble drugs which usually remain entrapped in the matrix.SEM images of a PVA/starch/alphaA film before (A) and after (B) the erosion.
authors.affiliation: Department of Chemical Engineering, Industrial Chemistry and Science of Materials, University of Pisa, Via Diotisalvi 2, 56126 Pisa, Italy.
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Coluccio
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ciardelli
authors.forename: Franca
authors.initials: F
authors.lastname: Bertoni
authors.forename: Davide
authors.initials: D
authors.lastname: Silvestri
authors.forename: Caterina
authors.initials: C
authors.lastname: Cristallini
authors.forename: Paolo
authors.initials: P
authors.lastname: Giusti
authors.forename: Niccoletta
authors.initials: N
authors.lastname: Barbani
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D002021:Buffers; D002110:Caffeine / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D011142:Polyvinyl Alcohol / Q000737:chemistry; D012995:Solubility; D012996:Solutions; D013213:Starch / Q000737:chemistry; D013696:Temperature; D013806:Theophylline / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D002021:Buffers; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D008567:Membranes, Artificial; D012996:Solutions; D014867:Water; D002110:Caffeine; D011142:Polyvinyl Alcohol; D013213:Starch; D013806:Theophylline