title: Controlled release of nafcillin using biocompatible "dummy" molecularly imprinted sol-gel nanospheres.
abstract: Different silicon-based xero-gel molecularly imprinted spheres in the nano boundary range with recognition capabilities for nafcillin have been synthesised, using tetraethylorthosilicate (TEOS) and (3- aminopropyl) triethoxysilane (APTEOS) as precursors. Imprinting has been achieved using both nafcillin (NAF) or structural analogous 'dummies' such as (+)-6-aminopenicillenic acid (APA), or ampicillin ((+)-6- aminobenzylpenicillin)sodium salt (AMP). Materials were fully characterized using ATR-FTIR, (29)Si solidstate NMR, TGA, TEM and BET. Adsorption isotherms for all the materials fit with a continuous Freundlich model with correlation coefficients better than 0.988 and mean affinity constants between 10(5) and 10(6) L·mol(-1). The use of 'dummies' as well as the template itself in the imprinting process resulted in materials with different release speed. Combinations of these materials allow designing mixtures with a continuous, controlled and constant release longer than four days. Thus, the non-imprinted and the AMP-imprinted material have a rapid release during the first five hours, nafcillin and APA imprinted ones release antibiotic mainly after a latency-period of 24 hours.
authors.forename: T Díaz-Faes
authors.initials: TD
authors.lastname: López
authors.forename: M A Escudero
authors.initials: MA
authors.lastname: Francos
authors.forename: A Fernández
authors.initials: AF
authors.lastname: González
authors.forename: M E
authors.initials: ME
authors.lastname: Díaz-García
authors.affiliation: Faculty of Chemistry, Department of Physical and Analytical Chemistry, University of Oviedo. Av. Julian Claveria, 8 33006-Oviedo, Spain. rbadia@uniovi.es.
authors.forename: R
authors.initials: R
authors.lastname: Badía-Laíño
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000138:chemical synthesis* / Q000737:chemistry; D065546:Drug Liberation; D005782:Gels; D007700:Kinetics; D008163:Luminescent Measurements; D054802:Molecular Imprinting / Q000379:methods*; D009254:Nafcillin / Q000737:chemistry*; D054118:Nanospheres / Q000737:chemistry*; D010406:Penicillins / Q000737:chemistry*; D044367:Phase Transition; D011437:Propylamines; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D010406:Penicillins; D011437:Propylamines; D012821:Silanes; C040733:tetraethoxysilane; D009254:Nafcillin; D012822:Silicon Dioxide; C477625:amino-propyl-triethoxysilane