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Publicaciones científicas más recientes (desde 2010)

Autores: García-Padial, Marcos; Martínez-Oharriz, M.C.; Isasi, José Ramón; et al.
Revista: JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
ISSN 0021-8561  Vol. 65  Nº 24  2017  págs. 4905 - 4910
The sorption and release of tyrosol and caffeic acid, two biophenolic antioxidants with known health benefits, in different insoluble cyclodextrin polymers have been studied. Cyclodextrin polymers were synthesized by cross-linking, beta-cyclodextrin or 50:50 w/w nominal mixtures of alpha- and beta-cyclodextrins using either epichlorohydrin (EP) or toluene-2,4-diisocyanate (TDI) as cross-linking agents. An analogous sucrose polymer was prepared using EP as cross-linking reagent. Freundlich isotherms and isosteric heats of sorption for tyrosol and caffeic acid in the insoluble beta-cyclodextrin polymer cross-linked with epichlorohydrin at 50 degrees C were obtained and discussed. Finally, the release of tyrosol and caffeic acid has been studied from loaded polymer disks, the microstructures of which were characterized by mercury intrusion porosimetry. Caffeic acid shows greater affinity than tyrosol for the polymeric matrices as it presents a higher sorption and a lower and slower release. However, tyrosol has a higher isosteric heat of sorption for low coverages.
Autores: González-Gaitano, Gustavo; Isasi, José Ramón; Vélaz, I.; et al.
Revista: CURRENT PHARMACEUTICAL DESIGN
ISSN 1381-6128  Vol. 23  Nº 3  2017  págs. 411 - 432
The pharmaceutical applications of cyclodextrins (CDs), cyclic oligosaccharides capable of including hydrophobic molecules inside their cavities, have been known for decades. Besides the solubilising and encapsulating abilities of natural and modified CDs due to the formation of inclusion complexes, there is an increasing interest in organized macrostructures based on CDs as potential drug delivery devices and gene carrier systems. The present review discusses first the case of drug carriers based on monomeric modified CDs (amphiphilic and CD core-star polymers), in which self-assembly plays a major role. Polyrotaxanes, i.e., CDs threaded onto a polymer chain, are then reviewed in relation to their pharmaceutical applications. Finally, covalently linked CDs, either by grafting or crosslinking, are analyzed, including more complex structures formed by assembling CD-containing networks or chains. We have tried along this review to cover the most recent developments on these structures for drug delivery in a "beyond the cyclodextrin" approach. The review will be helpful, both for readers who want to be introduced into the world of these remarkable structures, or for specialists who are doing research in this field.
Autores: Lucio, David; Zornoza, Arantza; Martínez-Oharriz, M.C.;
Revista: INTERNATIONAL JOURNAL OF PHARMACEUTICS
ISSN 0378-5173  Vol. 467   Nº 1 - 2  2014  págs. 19 - 26
The interactions of diflunisal (DF) with chitosans (CS) of different molecular weights and carboxymethylchitosan (CMCS), a water-soluble derivative, have been investigated. The interactions in solution have been studied by solubility assays in which the highest solubilisation (13-fold) was obtained with CMCS. Solid dispersions were prepared by coevaporation and kneading methods. Solid state characterisation was performed by X-ray diffraction analysis, scanning electron microscopy, thermomicroscopy, differential thermal analysis and infrared spectroscopy. Drug-polymer electrostatic interactions and hydrogen bonds are the main binding forces in these systems. The kneading method gave rise to amorphous systems regardless of the polymer employed. However, coevaporation resulted in the formation of different polymorphs of diflunisal (form II or III) depending on the type of polymer used. Therefore, it seems that drug-polymer interactions determine the crystallization pattern of the drug. Finally, diflunisal release from these systems improved markedly with CMCS and significantly in the presence of low molecular weight CS.
Autores: García-Padial, Marcos; Martínez-Oharriz, M.C.; Isasi, José Ramón; et al.
Revista: JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
ISSN 1388-3127  Vol. 75  Nº 3-4  2013  págs. 241 - 246
Tyrosol (TY), 4-(2-hydroxyethyl)phenol, is an olive oil biophenol with antioxidant activity and positive effects on human health. This study has investigated the interactions of TY with cyclodextrins (CD) and a CD polymer. Complexation of TY with beta-CD, hydroxypropyl-beta-CD (HP-beta-CD), and methyl-beta-CD (Me-beta-CD) has been evaluated both in aqueous solution and in the solid state. The techniques employed in solution to determine the apparent stability constants of the respective complexes were fluorescence and UV-visible spectroscopies. Complexation with beta-CD and its derivatives involved an increase of both the UV absorbance and the intrinsic fluorescence of TY; a bathochromic shift of the UV spectrum was detected as well. The apparent stability constants obtained with native beta-CD, Me-beta-CD and HP-beta-CD presented similar values. Complexes in the solid state were obtained by coevaporation and kneading. They were characterised by X-ray diffraction analysis and differential thermal analysis. The interaction of TY with beta-CD led to a crystalline complex; the same diffraction pattern was obtained by coevaporation and kneading. The complexes obtained with methyl- and HP-beta-CD were amorphous irrespective of the preparation method. In addition, the retention of TY in an insoluble polymer of CD crosslinked with epichlorohydrin has been quantified. In approximately 20 min, 1 mg of TY per gram of polymer was retained.
Autores: García-Padial, Marcos; Martínez-Oharriz, M.C.; Navarro-Blasco, I.; et al.
Revista: JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
ISSN 0021-8561  Vol. 61  Nº 50  2013  págs. 12260 - 122604
Tyrosol and caffeic acid are biophenols that contribute to the beneficial properties of virgin olive oil. The influence of hydroxypropyl-beta-cyclodextrin (HP beta-CD) on their respective antioxidant capacities was analyzed. The ORAC antioxidant activity of tyrosol (expressed as mu M Trolox equivalents/mu M Tyrosol) was 0.83 +/- 0.03 and it increased up to 1.20 +/- 0.11 in the presence of 0.8 mM HP beta-CD. However, the ORAC antioxidant activity of caffeic acid experienced no change. The different effect of HP beta-CD on each compound was discussed. In addition, the effect of increasing concentrations of different cyclodextrins in the development of ORAC-fluorescence (ORAC-FL) assays was studied. The ORAC signal was higher for HP beta-CD, followed by M beta-CD, beta-CD, gamma-CD and finally alpha-CD. These results could be explained by the formation of inclusion complexes with fluorescein.
Autores: Zornoza, Arantza; Isasi, José Ramón; et al.
Revista: Journal of Inclusion Phenomena and Macrocyclic Chemistry
ISSN 1388-3127  Vol. 69  Nº 3-4  2011  págs. 469 - 474
Autores: Fernández, L.; Zornoza, Arantza; et al.
Revista: Journal of Inclusion Phenomena and Macrocyclic Chemistry
ISSN 1388-3127  Vol. 69  Nº 3-4  2011  págs. 411 - 415
Autores: Maddens, T.; Vélaz, I.; et al.
Revista: Journal of Inclusion Phenomena and Macrocyclic Chemistry
ISSN 1388-3127  Vol. 70  Nº 3-4  2011  págs. 415 - 419
Autores: Zornoza, Arantza; et al.
Revista: Journal of Inclusion Phenomena and Macrocyclic Chemistry
ISSN 1388-3127  Vol. 66  Nº 3-4  2010  págs. 393 - 402
Terbinafine (TB) is an allylamine derivative used as oral and topical antifungal agent. The physicochemical properties of the complexes between TB and different cyclodextrins (CDs): alpha-CD, beta-CD, hydroxypropyl beta-CD, methyl beta-CD and gamma-CD, have been studied in pH 12 aqueous solutions at 25 A degrees C and in the solid state. Different phase solubility profiles of TB in the presence of CDs have been obtained: A(L) type for TB with hydroxypropyl beta-CD and gamma-CD, A(P) type for the complexes with methyl beta-CD and alpha-CD, while a B(S) profile was found for TB-beta-CD. The apparent stability constants of the complexes were calculated at 25 A degrees C from the phase solubility diagrams. The higher increase of TB solubility, up to 200-fold, together with the higher value of the stability constant were found for the complex with methyl beta-CD. Solid systems of 1:1 drug:CD molar ratio were prepared and characterised using X-ray diffraction patterns, thermal analysis and FTIR spectroscopy. The coevaporation method can be considered the best method in preparing these solid complexes. The complexes of TB with natural CDs, except with alpha-CD, were crystalline, whereas the methyl and hydroxypropyl derivatives gave rise to amorphous phases. Dissolution rate studies have been performed with TB-beta-CD and TB-HP beta-CD complexes, showing a positive influence of complexation on the drug dissolution.