In vivo toxicity and biodistribution of intravenously administered antibiotic-functionalized gold nanoparticles

The utilization of engineered gold nanoparticles (GNPs) in biomedical applications is experiencing rapid growth owing to their reactive nature and remarkable flexibility. However, despite these advantages, concerns persist regarding their in vivo biocompatibility and cytotoxicity. This study aimed to assess the toxicity, biodistribution, and excretion pathways of GNPs functionalized with various antibiotics, namely, ciprofloxacin, levofloxacin, cefotaxime, and ceftriaxone, using a mouse model. Following intravenous administration, the nanostructures induced an increase in serum enzyme levels and histological abnormalities in the liver, indicating potential hepatotoxic effects. Analysis of organ distribution revealed accumulation primarily in the liver and spleen, with concentrations gradually decreasing 168-h post-administration. Fecal excretion was identified as the primary route of elimination, with a smaller portion excreted via urine. Among the different nanostructures evaluated, those functionalized with levofloxacin (LEV-NP) exhibited minimal organ toxicity and a high clearance rate. Additionally, LEV-NP, with a size of approximately 12 nm, demonstrated superior drug particle stability and lower red blood cell hemolytic activity compared to other nanostructures.