DEVELOPMENT AND EVALUATION OF PLGA NANOPARTICLES LOADED WITH LEVOFLOXACIN FOR TUBERCULOSIS TREATMENT

Tuberculosis (TB) is one of the leading causes of death from infectious disease worldwide. Studies show that levofloxacin has potential to reduce infection progression in individuals exposed to multidrug-resistant TB. However, limitations such as low bioavailability, adverse effects, and an unfavorable pharmacokinetic profile restrict its clinical efficacy. Nanoparticles, due to their ability to provide controlled drug release, stand out as a promising approach in research for respiratory diseases, enabling more effective administration routes such as oral and inhaled delivery. PLGA (poly(lactic-co-glycolic acid)), a biodegradable polymer used as a carrier, improves drug stability, release, and bioavailability, potentially reducing side effects and increasing therapeutic efficacy. In this context, this study aimed to develop and characterize PLGA nanoparticles containing levofloxacin, evaluating their antimicrobial activity against the Mycobacterium tuberculosis strain. PLGA nanoparticles loaded with levofloxacin were prepared by the double emulsification method (water-in-oil-in-water, W/O/W) with solvent evaporation, using PLGA and polyvinyl alcohol (PVA) as the stabilizer. The formulations were characterized by dynamic light scattering (DLS) for mean diameter (Z-Ave), polydispersity index (PDI), and zeta potential (ZP). Encapsulation efficiency was determined by UV-Vis spectrophotometry. The antibacterial activity of the nanoparticles was determined through the Minimum Inhibitory Concentration using the colorimetric microdilution method against the reference strain H37Ra. The produced formulations showed Z-Ave of 181.17±2.44, PDI of 0.040±0.02, and ZP of -9.33 mV, indicating homogeneous distribution and satisfactory colloidal stability. Encapsulation efficiency was 40.23%. The MIC against the H37Ra strain was 1.09 µg/mL for the nanoparticle, compared with 1 µg/mL for free levofloxacin. The nanoparticles showed adequate physicochemical properties, high homogeneity, and potential antimicrobial activity against the Mycobacterium tuberculosis H37Ra strain. The results indicate that nanoencapsulation may represent a promising strategy to improve TB treatment, especially in cases of drug resistance.