Radiation-induced PEGylated Ethambutol Has Low Antimycobacterial Activity in Vitro

Tuberculosis is an airborne disease caused by Mycobacterium tuberculosis and remains one of the leading causes of death worldwide. The rise in multidrug-resistant strains has prompted the search for novel strategies to produce tuberculostatic agents. This research is aimed at developing a derivative of ethambutol by gamma radiation-induced polymerization with polyethylene glycol (PEG). The synthesis was verified by Raman spectroscopy and UV–Vis spectrometry. The results show that PEG can be chemically bonded to ethambutol by amine and alcohol groups. In in vitro biological evaluation, PEGylated and neat ethambutol showed similar cell viabilities, while the modified drug lowered bacterial growth inhibitory activity. A mechanism for the polymerization is proposed. The particle size increased for PEGylated drugs concerning the starting polyether. Despite the low antimycobacterial activity in vitro, the product seems to be a promising tool for the rapid screening of hydrolase activity.