Nanopartículas de PLGA-quitosana contendo dexametasona: desenvolvimento, caracterização e avaliação da atividade anti-inflamatória in vitro

Abstract

The objective of this work was to develop and characterize nanoparticles (NP) consisting of PLGA and coated with chitosan (QT) for the encapsulation of dexamethasone (DEX), aiming to increase the efficacy of this drug in the context of the treatment of severe acute respiratory syndrome (SARS) related to COVID-19. For this purpose, DEX acetate (DEXAc) or DEX disodium phosphate were used for the development of PN. The use of DEXAc provided greater encapsulation efficiency (EE) of the drug in the PN and, therefore, this formulation was chosen for subsequent trials. NP-DEXAc were coated with QT (NP-DEXAc-QT) and characterized in relation to mean hydrodynamic diameter (DHm), polydispersity index (PdI), zeta potential (PZ), morphology, encapsulation efficiency (EE) and drug loading (DL). In addition, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyzes were conducted. Cytotoxicity in J774.A1 strain (murine macrophages) and in vitro anti-inflammatory activity after stimulation of these strain with LPS or LPS+IFN-γ and subsequent quantification of nitric oxide (NO), IL-6, IL- 12 and TNF-α were also evaluated. The developed formulations showed characteristics of monodisperse systems (PdI < 0.3). The DHm of NP-DEXAc-QT (264.4 ± 4.4 nm) was higher than that obtained for NP-DEXAc (207.3 ± 6.7 nm). Furthermore, after coating, there was an inversion of the PZ of the NP-DEXAc (-11.83 ± 1.4 mV) to positive values (+30.0 ± 1.6 mV). Furthermore, the microscopy analyzes showed that the coating made the surface of the PN smoother. Analyzed together, these data may indicate that the NP were efficiently coated by QT. The EE was high for both formulations, with results equal to 83.7 ± 1.04% (LD = 6.96 ±0.09%) for NP-DEXAc and 78.5 ± 0.26% (DL = 6.53 ± 0.02%) for QT-DEXAc-NP. DRX and FTIR analyzes confirmed the encapsulation of DEXAc within the polymeric matrix, as well as the occurrence of NP coating by QT. There was no evidence of cytotoxicity up to concentrations of 200 µg/mL and 400 µg/mL for DEXAc-NP and QT-DEXAc-NP, respectively. This result may indicate that CT increases the cells' tolerance to nanoparticles. Regarding the anti-inflammatory activity, the NP-DEXAc-QT provided a significant reduction in the levels of NO and cytokines compared to the control group (stimulated and untreated cells), in addition to presenting a comparable effect to the free drug. Thus, the results obtained indicate that QT-coated nanoparticles have promising characteristics for the delivery of DEXAC aimed at application in the treatment of SARS associated with COVID-19.