title: Sorption and release of drugs in/from cross-linked poly(ethyleneimine) multilayer films deposited onto silica microparticles.
abstract: Multilayer thin films are useful materials in fabrication of controlled drug delivery systems and in controlling drug release processes. Herein, we report the fabrication of single polycation multilayers based on branched poly(ethylene imine) (PEI) mediated by dianhydrides (DA), as cross-linker and source of carboxylic groups, deposited onto Daisogel silica microparticles, and their sorption/release properties for some anionic drugs as a function of the cross-linker concentration. Pyromellitic dianhydride (PM) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTCDA) were used as DA reagents. The monotonous increase of the (PEI-DA)n multilayers was demonstrated by Fourier transform infrared spectroscopy, point of zero charge (pzc), and X-ray photoelectron spectroscopy. The sorption properties of the PEI multilayer films for two drugs (diclofenac sodium, DS, and indomethacin, IDM) and a model dye (Ponceau SS, PSS) were influenced by the number of PEI layers and the weight ratio between cross-linker and silica microparticles during the cross-linking steps. It was found that the adsorbed amount of drugs increased with the number of PEI layers and with the decrease of DA concentration. The Langmuir, Sips, and Dubinin-Radushkevich model isotherms were applied to fit the sorption equilibrium data of IDM onto the Daisogel//(PEI-DA)n composites. The maximum equilibrium sorption capacity, qm, evaluated by the Langmuir model, at 25 °C, was 37.05 mg IDM/g of Daisogel//(PEI-BTCDA)8.5, and 39.99 mg IDM/g of Daisogel//(PEI-PM)8.5, for a weight percentage of DA/silica of 0.1% w/w. Cumulative release of DS was almost 100% within 180 min, while IDM was desorbed at a level of 35%, in 320 min, supporting a sustained release was gained with the cross-linked PEI films. The stability of the (PEI-DA)n multilayers during the successive sorption/desorption cycles of PSS was demonstrated.
authors.affiliation: "Petru Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania.
authors.forename: Florin
authors.initials: F
authors.lastname: Bucatariu
authors.affiliation: "Petru Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania.
authors.forename: Claudiu-Augustin
authors.initials: CA
authors.lastname: Ghiorghita
authors.affiliation: "Petru Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania. Electronic address: sdragan@icmpp.ro.
authors.forename: Ecaterina Stela
authors.initials: ES
authors.lastname: Dragan
mesh_terms: D000327:Adsorption; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004008:Diclofenac / Q000737:chemistry*; D065546:Drug Liberation; D007213:Indomethacin / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D003432:Cross-Linking Reagents; D004008:Diclofenac; D012822:Silicon Dioxide; D011094:Polyethyleneimine; D007213:Indomethacin
keywords: Cross-linking; Dianhydride; Diclofenac sodium; Indomethacin; Poly(ethyleneimine) multilayer; Ponceau SS