EVALUATION OF THE ANTIMYCOBACTERIAL POTENTIAL OF RIFAMPICIN NANOENCAPSULATED IN PLGA 75:25

Tuberculosis (TB), mainly caused by Mycobacterium tuberculosis (Mtb), represents one of the major global public health problems. This scenario is aggravated by the emergence of resistant strains, often resulting from treatment abandonment due to the long duration of therapy and adverse effects of available drugs. Rifampicin (RIF) is one of the main drugs used in TB treatment; however, it presents limitations such as low solubility and stability. Encapsulation in polymeric nanostructures, such as PLGA (poly(lactic-co-glycolic acid)), emerges as an alternative to improve the therapeutic performance of these drugs. Thus, this study aimed to develop and characterize a PLGA nanoformulation containing RIF and to analyze its in vitro inhibitory potential. The nanoformulation was obtained using the single emulsion method, with rifampicin as the model drug, PLGA 75:25 as the polymeric matrix, and PVA as stabilizer. The formulations were evaluated for average diameter (Z-Ave), polydispersity index (PdI), zeta potential (ZP), and encapsulation efficiency (EE%) by DLS and UV-VIS, respectively. In vitro antimycobacterial activity was determined against the sensitive Mtb strain H37Ra by plate microdilution using resazurin as the revealing solution. The obtained nanoparticles (N-PLGA75:25-RIF) showed a Z-Ave of 224.27±5.19 nm, PdI of 0.14±0.04, ZP of -13.10±0.56 mV, indicating homogeneity and adequate colloidal stability, and EE% of 13%. In the in vitro assay, N-PLGA75:25-RIF achieved inhibition at 0.125 µg/mL, twice as potent as free RIF (0.250 µg/mL). Based on the obtained results, it can be concluded that it was possible to develop a PLGA 75:25 nanoformulation containing RIF with suitable physicochemical parameters and superior antimycobacterial activity compared to the free drug. Thus, the produced data reinforce the potential of the nanoformulation as a promising alternative for improving tuberculosis therapy.