Bio-compatible delivery system design for metformin: Characterization, radiolabeling ve in vitro studies

In this study, it is aimed to synthesize metformin (MET) loaded solid lipid nanoparticles and radiolabeled with technetium-99m (I) tricarbonyl core and to evaluate its biological behaviour of designed system in vitro. Structural characterization of synthesized solid lipid nanoparticles (SLN) was performed by Dynamic Light Scattering (DLS) method, Zeta Potantial Analysis, Scanning Electron Microscopy (SEM) imaging. Metformin loaded solid lipid nanoparticles were radiolabeled with technetium-99m (I) tricarbonyl core. Quality control studies of metformin loaded radilabeled solid lipid nanoparticles (99mTc(CO)3-MET-SLN) were performed by High Liquid Radiochromatography and Thin Layer Radiochromatography methods. A drop of the radiolabeled formulation was applied on to TLRC (Thin Layer Radiochromatography) silica gel coated strip, which were run in 100% acetonitrile and Met:HCl (Methanol: Hydrochloric acid in ratio19:1). The radiolabeling efficiency of metformin loaded solid lipid nanoparticles [99mTc(CO)3-MET-SLN] was 88%. Quality control studies of 99mTc(CO)3-MET-SLN were performed by High Liquid Radiochromatography and Thin Layer Radiochromatography methods. On the other hands, metformin loaded solid lipid nanoparticles were conjugated with inactive rhenium (I) tricarbonyl core. This allowed the determination of the structure of radiolabeled nanoparticles. Studies have been performed on cancer lines ( MCF7, MDA-MD-231 breast and HEPG2 liver cancer cells) to determine the biological behaviour of metformin loaded solid lipid nanoparticles in vitro. Estrogen receptor positive MCF7 breast cancer cells were more than sensitive than estrogen receptor negative MDA-MB-231 breast cancer cells and HEPG2 liver cancer cells to metformin loaded solid lipid nanoparticles, indeed 50% inhibiton of growth was achieved with about 300 µg/mL of MET-SLN and the cytotoxicity increased on increasing the concentration. Higher uptake values of 99mTc(CO)3-MET-SLN were determined on receptor estrogen positive MCF7 breast cancer cell line according to receptor estrogen negative MDA-MB-231 breast cancer and HEPG2 liver cancer cell lines.