Optimization of Polylactide-Co-Glycolide-Rifampicin Nanoparticle Synthesis, in Vitro Study of Mucoadhesion and Drug Release

Despite the large number of works on the synthesis of polylactide-co-glycolide (PLGA) nanoparticles (NP) loaded with antituberculosis drugs, the data on the influence of various factors on the final characteristics of the complexes are quite contradictory. In the present study, a comprehensive analysis of the effect of multiple factors, including the molecular weight of PLGA, on the size and stability of nanoparticles, as well as the loading efficiency and release of the antituberculosis drug rifampicin (RIF), was carried out. Emulsification was carried out using different surfactants (polyvinyl alcohol, Tween 80 and Pluronic F127), different aqueous-to-organic phase ratios, and different solvents (dichloromethane, dimethyl sulfoxide, ethyl acetate). In this research, the PLGA nanoemulsion formation process was accompanied by ultrasonic dispersion, at different frequencies and durations of homogenization. The use of the central composite design method made it possible to select optimal conditions for the preparation of PLGA-RIF NPs (particle size 223 ± 2 nm, loading efficiency 67 ± 1%, nanoparticles yield 47 ± 2%). The release of rifampicin from PLGA NPs was studied for the first time using the flow cell method and vertical diffusion method on Franz cells at different pH levels, simulating the gastrointestinal tract. For the purpose of the possible inhalation administration of rifampicin immobilized in PLGA NPs, their mucoadhesion to mucin was studied, and a high degree of adhesion of polymeric nanoparticles to the mucosa was shown (more than 40% within 4 h). In the example of strain H37Rv in vitro, the sensitivity of Mycobacterium tuberculosis to PLGA-RIF NPs was proven by the complete inhibition of their growth.