In this work, poly(lactic-co-glycolic acid) (PLGA) and chitosan (CS) nanoparticles were
synthesized with the purpose of encapsulating levofloxacin (LEV). A thorough study has been carried
out in order to optimize the preparation of LEV-loaded polymeric nanoparticles (NPs) suitable for
parenteral administration. Changes in the preparation method, in the organic solvent nature, in the
pH of the aqueous phase, or in the temperature were investigated. To the authors´ knowledge,
a systematic study in order to improve the LEV nanocarrier characteristics and the yield of drug
encapsulation has not been carried out to date. The physicochemical characterization of the NPs,
their encapsulation efficiency (EE), and the in vitro release of LEV revealed that the best formulation
was the emulsion-solvent evaporation method using dichloromethane as organic solvent, which
renders suitable LEV loaded PLGA NPs. The morphology of these NPs was investigated using TEM.
Their antimicrobial activities against several microorganisms were determined in vitro measuring the
minimum inhibitory concentration (MIC). The results show that the use of these loaded LEV PLGA
nanoparticles has the advantage of the slow release of the antibiotic, which would permit an increase
in the time period between administrations as well as to decrease the side effects of the drug.