Antibacterial Activity and <i>In Vitro</i> Cytotoxicity of Colistin in Sodium Deoxycholate Sulfate Formulation

Abstract

Colistin has its problem with nephrotoxicity despite its capability for combatting multi-drug resistant gram-negative bacteria. Sodium deoxycholate sulfate (SDCS) has been shown to increase the safety profile of nephrotoxic drugs. This study aimed to explore the antimicrobial activity of colistin-SDCS versus free colistin against P. aeruginosa and investigate their cytotoxicity on kidney cells. The colistin micelles were formulated with SDCS followed by lyophilization and their properties were analyzed. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of colistin were determined using the broth microdilution method. The static time-kill kinetics were also employed to monitor the bactericidal activity of formulation over time. The cytotoxicity of formulations was analyzed using MTT colorimetric assay against kidney cells. The colistin-SDCS dry-powder was stable after reconstitution and resulted in 240 to 297 nm in particle size with the zeta potential of -22.8 to -23.4 mV. The colistin-SDCS formulations showed similar antibacterial activity against P. aeruginosa to pure colistin. MIC and MBC were 7.81 and 15.63 µg/mL, respectively. The static-time kill results displayed slightly better bactericidal activity at 24 h. The viability of kidney cells exposure to colistin-SDCS micelle was higher than that of pure colistin.