Production and characterization of multifunctional poly(lactic-co-glycolic acid) nanoparticles

The promising results in increasing the effectiveness of active ingredients, reducing toxicity, and increasing/enhancing stability in studies with nanoparticular systems; make nanoparticles a preferred tool in the fields of nanotechnology, medicine, and biotechnology. Poly(lactic-co-glycolic acid) (PLGA), which is polymeric in structure within nanoparticular systems, is widely used for the encapsulation of various therapeutic agents due to its high biodegradability, biocompatibility, low toxicity/low immunogenicity, suitable mechanical properties, and non-toxicity of degradation products. In this study, for the first time, caffeic acid phenethyl ester (2-Phenylethyl-3-(3,4-dihydroxyphenyl)acrylate, CAPE), a natural bioactive component of propolis, and juglone (5-hydroxy-1,4-naphthoquinone), an active compound isolated from the walnut tree, molecules were used together as active ingredients, encapsulated into a single polymeric nanoparticle and hereby multifunctional nanoparticles were produced. In addition, antibacterial activities of active ingredients and nanoparticle formulations containing CAPE and juglone molecules together were also investigated for the first time in this study. Nanoparticular systems have advantages such as to increase the biocompatibility of the active ingredients, to reduce toxicity and to provide the use of less active ingredient with controlled release. In this thesis, PLGA nanoparticles containing different ratios of CAPE and juglone active ingredients, which have antibacterial properties, were prepared using oil in water (o/w) single emulsion solvent evaporation method. Detailed characterization of the produced nanoparticles was performed by encapsulation efficiency, drug loading, reaction yield, size, zeta potential, FT-IR, SEM analyzes and in vitro release studies. The antimicrobial activity of the produced nanoparticles was determined by broth microdilution, agar well diffusion and disk diffusion methods and MIC values and inhibition zone diameters were recorded. Monodisperse spherical nanoparticles with sizes ranging from 151.4±6.0 to 196.0±0.7 nm were obtained by the o/w single emulsion solvent evaporation method. In in vitro release studies, nanoparticles exhibited a rapid release within the initial 3 hours. Unlike previous studies, more effective antibacterial activity was detected in multifunctional nanoparticles containing CAPE and juglone molecules together because of the synergistic effect of active ingredients.