Antibiotic-loaded pMMA nanofiber mats as antibacterial material: Comparative analysis of levofloxacin and chloramphenicol release

In this work, we fabricated polymer mats consisting of polymethyl methacrylate (PMMA) nanofibers loaded with antibiotic levofloxacin (LV) or chloramphenicol (CAM) and characterized them using microscopic method, UV-visible absorption spectroscopy, and mass spectrometry. The diameter of the obtained nanofibers ranged from 1 to 4 μm. We analyzed the kinetics of the drug release from the mats and studied their antibacterial properties. The antibiotics release from the nanofiber mat when soaked in an aqueous solution was studied using UV-Vis spectroscopy. LDI mass spectrometry probing of saline extracts from the mats loaded by LV or CAM demonstrated the presence of abundant peaks of molecular ions of both antibiotics in the spectra. Such result confirms the preservation of the molecular structure of most LV molecules, as well as CAM molecules during the processes of antibacterial mat fabrication and drugs extraction from the mats, which is important for keeping their antibacterial properties. UV-Vis spectroscopy observations showed that ≈50% of LV was released into the aqueous solution within the first 10 min, and the remaining 20% within the next 3 h. In contrast, the release time of CAM was significantly longer: only 10% of the CAM was released from the mat within the first 5 h, and the next 5% required 45 h. The overall release fraction was only 35%, which took about 650 h. It is supposed that LV exhibits a faster and more intense release due to its hydrophilicity and weaker binding to PMMA, while CAM demonstrates a slower and more incomplete release due to its lower water solubility and stronger binding with the hydrophobic PMMA matrix. The antibacterial properties of the antibiotic-loaded nanofiber matrix were studied against Gram-positive and Gram-negative bacteria. The study revealed that both types of mats demonstrated high efficacy against these bacteria, with the exception of CAM, which showed lower activity against P. aeruginosa 9027.