Structural characterization and in vitro behavior of aspirin-containing hybrid microspheres

HERNÁN E. ROMEO; ROBERTO J. J. WILLIAMS; MARÍA A. FANOVICH

Los Cocos, Córdoba, Argentina

Simposio; V Simposio Argentino-Chileno de Polímeros (ARCHIPOL 2009); 2009

Different kinds of polymers have been employed in medicine as biomaterials. Artificial heart, dialysis membranes and sacaffolds for tissue engineering are some of the devices commonly reported [1]. In recent years, considerable attention has been focused on the development of drug delivery systems to increase bioavailability and sustain drug action in human body. However, the really absorbed amount of drug is difficult to control and release kinetics is often quite variable. In this way, microencapsulation of drugs has been proposed to solve these problems, being polymer microparticles widely employed as supports to deliver drugs, either as microspheres or microcapsules [2]. In addition to traditional polymer materials, spherical particles of different nature have attracted great attention in advanced technologies. If a patterned structure can be generated inside the spheres, some new properties which can not be obtained from non-structured spheres, are expected. Bridged silsesquioxanes are a family of organic-inorganic hybrid materials which has been recognized to have an enormous potential as building block for various nanostructured materials. Depending on the nature of the bridge, which could exhibit self-assembling properties, different degree of organization at molecular level can be achieved during the hydrolytic condensation of the precursors. In the last years, the chemical applications of ultrasound have become an exciting new field of research [3]. In particular, the applications of ultrasound to the synthesis of biomaterials are under rapid development, being protein microencapsulation and preparation of long-lived proteinaceous microspheres two of the most common uses frequently reported. The aim of this work was to synthesize aspirin (AS)-containing hybrid microspheres (HM) of a bridged silsesquioxane via ultrasound-assisted self-assembly of a bridged pecursor. Based on the self-assembling properties of this bridged precursor, the structured microspheres could incorporate AS in the resulting matrix at molecular level. The AS-release behavior of these novel microspheres was tested under physiological conditions. In order to employ these HM in advanced biomedical technologies, preliminar in vitro cytotoxicity tests were performed on the synthesized material.