Grupo de Nuevos Materiales y Espectroscopia Supramolecular

Leioa, Spain

Grupo de Nuevos Materiales y Espectroscopia Supramolecular

Leioa, Spain
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Aguero L.,University of Habana | Garcia J.,University of Habana | Valdes O.,University of Habana | Fuentes G.,University of Habana | And 3 more authors.
Journal of Applied Polymer Science | Year: 2013

Free radical copolymerization of acryloxyethyl-trimethylammonium chloride with 2-hydroxyethyl methacrylate using sodium persulfate as initiator was carried out at 60°C and of its electrostatic interaction with sodium alginate (NaAlg) allowed obtaining polymeric microparticles by complex coacervation. The solute transport in this swellable matrix was investigated to check the effect of cross-linking and simulated physiological condition over release process. Cefazolin Sodium loaded microparticles were prepared by incorporation of drug directly in the reaction mixture and their ability of releasing resulted in more extensive in enzyme-free simulated intestinal medium. The polymeric microparticles prepared in this study were characterized by scanning electron microscopy showing irregular spherical form and rough structure. Particles showed unimodal distribution and the size distribution ranged from 1.1 to 1.8 mm (n = 100). © 2012 Wiley Periodicals, Inc.


Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Guerrero L.G.,University of Guadalajara | Mendizabal E.,University of Guadalajara
Frontiers in Bioscience - Elite | Year: 2012

In this work the synthesis of smart nanoparticles capable of respond to external stimulus (pH and temperature variations) is reported. To avoid postpolymerization modification, functionalized monomers able to respond to pH and temperature changes were and then polymerized. The synthesized monomers have the capability for coupling with folic acid which is the target molecule. For this reason their polymers can be used as targeted drug delivery systems. Smart polymeric nanoparticles were prepared by direct and inverse microemulsion polymerization of the synthesized monomers. The nanoparticles were charged with drugs and their release kinetic was studied.


Arellano J.,University of Guadalajara | Flores J.,University of Guadalajara | Zuluaga F.,University of Valle | Mendizabal E.,University of Guadalajara | Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2011

Here, we present the oil/water (O/W) microemulsion polymerization in three-component microemulsions of n-butyl acrylate, ethyl acrylate, and methyl acrylate, monomers with similar chemical structures but different water solubilities using the cationic surfactant dodecyl trimethyl ammonium bromide. The effects of monomer water solubility, initiator type and initial monomer concentration on the polymerization kinetics were studied. Reaction rates were high with final conversions between 70 and 98% depending on the monomer and reaction conditions. The final latexes were bluish, with a particle size ranging between 20 and 50 nm and polymer with molar masses in the order of 10 6 g mol-1. Increasing monomer water solubility resulted in a slower reaction rate, larger particles and a lower number density of particles. A higher reaction rate, larger average particle size and higher particle number density were obtained by increasing the monomer concentration. © 2011 Wiley Periodicals, Inc.


Castro E.,University of Santiago de Compostela | Mosquera V.,University of Santiago de Compostela | Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular
Nanomaterials and Nanotechnology | Year: 2012

We used temperature-sensitive poly(Nisopropylacrylamide) hydrogels as drug delivery systems, so changes in body temperature induced by pathogens could act like external stimuli to activate controlled release of the drugs incorporated in the hydrogel. In the distilled water combined release studies, we chose two model drugs: aminophylline and triamterene. The amount of drug released was measured by UV-Vis spectroscopy following the evolution of the absorption peaks of aminophylline (271 nm) and triamterene (365 nm). The maximum release time was greater for triamterene than for aminophylline at 37 °C, so these time-release profiles enabled the active ingredients to work over different periods of time. By increasing molar mass or solubility of the drug, we observed that the diffusion coefficient decreased. On the contrary, increasing hydrophobicity of the drug leads to a diffusion coefficient increase. The evolution of pore size distribution of hydrogels during loading and releasing was measured by quasi-elastic light scattering and by environmental electronic scanning microscope. When loading and releasing the drugs, the pore size of the hydrogel decreased and increased again without reaching the initial pore size of the hydrogel, respectively. We observed that the greater the concentration of drug loaded into the hydrogel, the greater the reduction in pore size. © 2012 Castro et al.


Gadea J.L.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Cesteros L.C.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular
European Polymer Journal | Year: 2013

New hydrogels based on polyethylene glycol (PEG) and poly(vinyl alcohol) (PVA) of different degrees of hydrolysis were synthesized. To form the network the PEG was modified at their ends with acyl chloride groups to be used as the crosslinking agent. The compositions of the hydrogels were between 50% and 90% by weight of PEG and PVA of various degrees of hydrolysis were used. It was found that the degree of hydrolysis of the PVA and the PEG content influence the equilibrium water content of the hydrogel. The process of swelling of all the hydrogels prepared followed a second-order kinetics. The pH of the medium influences the rate and degree of hydration of the hydrogel, this influence being less noticeable at lower pH values. At pH of 7.0 and above because the hydrolysis of the ester bonds which act as crosslinking points the swelling increases noticeably. The rate of hydrolysis of the hydrogels is greatly influenced by the degree of hydrolysis of the PVA used in their synthesis. The degree of hydration decreases with temperature because their entropy of mixing is negative; however, when the pH of the medium favors the process of hydrolysis, an increase in temperature accelerates this process, which causes a progressive increase in their degree of hydration. © 2013 Elsevier Ltd. All rights reserved.


Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Alvarez-Bautista A.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Mendizabal E.,University of Guadalajara | Guerrero-Ramirez L.G.,University of Guadalajara | And 2 more authors.
Advanced Materials Letters | Year: 2013

A series of star-shaped poly(acrylamide-co-[2-(acryloyloxy)ethyl] trimethyl ammonium chloride) were prepared by inverse microemulsion polymerization. The growth of side chains in the arms of the precursor has been carried out using different compositions of the comonomers acrylamide and [2-(acryloyloxy)ethyl] trimethyl ammonium chloride) (Q9). The characterization and star structure were determined by nuclear magnetic resonance, FTIR, MALDI-TOF and DSC. The dimensions of the particles were determined by quasielastic light scattering and transmission electron microscopy. Quasi-spherical particles of star polymers in the nanozise range were obtained which might be useful for the controlled transport and release of several biologically active drugs. © 2013 VBRI Press.


Valdes O.,University of Habana | Alexandrova L.,National Autonomous University of Mexico | Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Zaldivar D.,University of Habana
Journal of Applied Polymer Science | Year: 2012

Interpenetrating polymeric networks (IPNs) based on natural sodium alginate (NaAlg) biopolymer matrix and synthetic hydrophilic polymer were synthesized using sequential method. Poly(acryloxyethyl-trimethylammonium chloride-co-2-hydroxyethyl methacrylate) (poly(Q-co-H)) with high content of quaternary ammonium groups (Q units) was used as a synthetic polymer for the purpose. Since NaAlg has anionic nature and poly(Q-co-H) is a polycation polyelectrolyte complex (PEC) was also prepared via ion interaction between these natural and synthetic components by mixing their water solutions. The all prepared materials were characterized by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (ATR-FTIR). The comparative analysis of IPNs of different compositions was carried out. Behavior of IPNs was also compared to PEC, material obtained via simple ionic interaction between oppositely charged polymers. © 2011 Wiley Periodicals, Inc.


Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Perez Ortiz J.A.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Mendizabal E.,University of Guadalajara
Chemical Engineering Science | Year: 2011

For two variable chemical oscillators, a simple strategy is to combine autocatalysis with a term including a binomial Michaelian denominator (constant+concentration). This strategy is applied in this paper to the context of polymerization reactions. In order to achieve autocatalysis a kinetic scheme of the form. is applied, where the dimeric form D is included. The Michaelian term can be obtained in different ways, for example: (i) a third compound Z flows through the system and eliminates the monomer, (ii) compound Z can be radical initiators, and (iii) compound Z, which eliminates monomer, can be a special conformation (adsorbent) of the polymer. Three mechanisms are developed using these Michaelian terms. After decreasing the number of variables to two, by assuming a non-significant variation of the others, and normalizing the kinetic equations with respect to a certain steady state, phase plane techniques are applied to prove the existence of a limit cycle in the three models. Both monomer concentration and propagator concentration in the three models (cases 2.1 and 2.2) or the concentration of the adsorbent polymers are taken as oscillating variables. © 2011 Elsevier Ltd.


Katime I.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Perez Ortiz J.A.,Grupo de Nuevos Materiales y Espectroscopia Supramolecular | Morales J.A.,University of Guadalajara | Mendizabal E.,University of Guadalajara
International Journal of Chemical Kinetics | Year: 2014

In this work, four polymerization mechanisms with flow are proposed where sustained oscillation can be present: (1) Polyaddition initiated by radicals produced by initiator decomposition, which is catalyzed by the polymer, first-order termination, a polymer disappears by a reaction with a third substance and by leaving the system in the exit flow. (2) Polycondensation where the polymer has catalytic activity upon H to produce a monomer, first-order termination and a monomer disappears by a reaction with a third substance, and there is exit flow for all the species. (3) Polycondensation with catalytic activity of the polymer upon A to produce a monomer, first-order termination, conformational transitions of the polymers, one of the polymer conformations disappears by a reaction with a monomer and exit flow for all the species. (4) Polycondensation combined with polyaddition where the polycondensation polymer product has catalytic activity on the monomer, first-order termination and exit flow of all the species. © 2014 Wiley Periodicals, Inc.


PubMed | Grupo de Nuevos Materiales y Espectroscopia Supramolecular
Type: | Journal: Frontiers in bioscience (Elite edition) | Year: 2011

In this work the synthesis of smart nanoparticles capable of respond to external stimulus (pH and temperature variations) is reported. To avoid post-polymerization modification, functionalized monomers able to respond to pH and temperature changes were and then polymerized. The synthesized monomers have the capability for coupling with folic acid which is the target molecule. For this reason their polymers can be used as targeted drug delivery systems. Smart polymeric nanoparticles were prepared by direct and inverse microemulsion polymerization of the synthesized monomers. The nanoparticles were charged with drugs and their release kinetic was studied.

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