PREPARATION AND PROPERTIES OF ALPHA-LIPOIC ACID-LOADED CHITOSAN NANOPARTICLES

The aim of this study was to prepare alpha-lipoic acid (ALA) loaded chitosan nanoparticles by the ionotropic gelation between chitosan and sodium pyrophosphate or tripolyphosphate and the use of the surfactant poloxamer 188 as a stabilizer. Their particle size and distribution along with their encapsulation efficiency and zeta potential was determined. The smallest particle size (180 nm) were obtained when sodium pyrophosphate was used as the polyanion. The addition of the poloxamer incresased the particle size independently of the polyanionic compound used. All the polydispersity indexes were > 0.2, indicating that all the chitosan nanoparticle systems were polydisperse. The highest encapsulation efficiency (62.4%) was obtained in the case of the tripolyphosphate and poloxamer system. The isoelectric point (pI) for all the chitosan nanoparticles lied in the 6.8 - 7.4 range. All the chitosan nanoparticles, with the exception of the ones prepared with TPP and poloxamer 188, were stable at pH values <= 5.3, indicating a good potential for use in foods.