FtsZ-IN-4, an orally active inhibitor of FtsZ (filamenting temperature-sensitive mutant Z), demonstrates remarkable antibacterial activity and favorable pharmaceutical properties. With low cytotoxicity (CC 50 >20 μg/mL) [1], FtsZ-IN-4 exhibits promising potential for therapeutic applications.

FtsZ-IN-4, identified as compound 30, exhibits potent antibacterial effects against B. subtilis and S. aureus, with minimum inhibition concentrations (MIC) of 0.008-0.25 μg/mL, according to standards [1]. This compound demonstrates rapid bactericidal activity, achieving significant reductions in bacterial population within 3 hours at concentrations of 0.064 μg/mL or 0.5 μg/mL, with minimum bactericidal concentration (MBC) to MIC ratios of ≤4, indicating efficacy within Clinical and Laboratory Standards Institute (CLSI) guidelines [1]. Additionally, at concentrations exceeding 20 μg/mL over 72 hours, FtsZ-IN-4 shows minimal cytotoxicity towards Vero cells, with a 50% cytotoxic concentration (CC50) >20 μg/mL [1]. It notably disrupts bacterial cell division, elongating B. subtilis ATCC9372 within 3 hours at 0.016 μg/mL and induces aberrant cell division leading to bacterial cell death [1]. Furthermore, FtsZ-IN-4 enhances SaFtsZ polymerization at 10 μg/mL within 0-15 minutes and inhibits SaFtsZ's GTPase activity in a dose-dependent manner within 30 minutes across concentrations of 0-35 μg/mL [1]. In cell proliferation assays, the compound significantly decreased populations of S. aureus ATCC25923 and B. subtilis ATCC9372 to below detectable limits within 3 hours at multiples of the MIC, establishing its effective bactericidal capabilities [1].

FtsZ-IN-4 (compound 30) exhibits moderate pharmacokinetic exposure (AUC (0-t) = 544.2 h*ng/mL) and an oral bioavailability (F) of 61.2% following a 5 mg/kg oral (p.o.) administration in mice [1]. At a 25 mg/kg intravenous (i.v.) dose, it effectively reduces bacterial burden in male ICR mice infected with S. aureus ATCC25923, achieving similar efficacy to vancomycin. Its pharmacokinetic profile includes a half-life (T 1/2) of 0.28 hours and a peak concentration (Cmax) of 480.5 ng/mL following a 1 mg/kg dose, further confirming its effectiveness when administered intraperitoneally [1].