Event Title

Identification and Stability of Fluoroquinolone Antibiotic Complexes Involving Heavy Metals, Ciprofloxacin, and Phenolic Degradation Products: Relevance in Ground and Waster Water Systems

Location

CSU 253/4/5

Start Date

4-4-2011 11:00 AM

End Date

4-4-2011 12:30 PM

Student's Major

Chemistry and Geology

Student's College

Science, Engineering and Technology

Mentor's Name

Trent Vorlicek

Mentor's Department

Chemistry and Geology

Mentor's College

Science, Engineering and Technology

Description

According to Pharmaceutical literature, metal-fluoroquinolone complexes are highly stable and often have increased antimicrobial activity relative to the uncomplexed fluoroquinolone. However, minimal research has been conducted regarding the role metal-fluoroquinolones play in environmental systems. This research aims to characterize novel metal-fluoroquinolones potentially relevant in ground and wastewaters. Stoichiometric analyses of aqueous test solutions showed highly insoluble ternary complex formation between cadmium (Cd; a heavy metal found in animal wastes), ciprofloxacin (a common veterinary fluoroquinolone antibiotic), and 4-nitrophenol (4-NP) or 2-chloro-4-nitrophenol (2C-4NP) at μM concentrations and pH = 7.0.

Experiments with 4-NP at varying pH demonstrated that the nitrophenolate form is required for ternary complexation. Solutions also containing Cd, ciprofloxacin, 2,6-dichloro-4-nitrophenol (2,6C-4NP) or 2- chloro-4,6-dinitrophenol (2C-4,6NP) formed insoluble 1:1 charge transfer complexes between ciprofloxacin and either nitrophenol. Charge transfer complexation may be due to the enhanced electrophilicity of these nitrophenols; steric hindrance may also partially explain the observed difference in complex type. For the eight phenols that were tested in this study, a nitro group in the para position appeared to be necessary for formation of the ternary or charge transfer complexes. Experiments to determine the stabilities of the ternary complexes are ongoing. These results are important because they point to an unaddressed reaction pathway available to heavy metals, powerful antibiotics, and toxic phenolic degradation compounds.

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Apr 4th, 11:00 AM Apr 4th, 12:30 PM

Identification and Stability of Fluoroquinolone Antibiotic Complexes Involving Heavy Metals, Ciprofloxacin, and Phenolic Degradation Products: Relevance in Ground and Waster Water Systems

CSU 253/4/5

According to Pharmaceutical literature, metal-fluoroquinolone complexes are highly stable and often have increased antimicrobial activity relative to the uncomplexed fluoroquinolone. However, minimal research has been conducted regarding the role metal-fluoroquinolones play in environmental systems. This research aims to characterize novel metal-fluoroquinolones potentially relevant in ground and wastewaters. Stoichiometric analyses of aqueous test solutions showed highly insoluble ternary complex formation between cadmium (Cd; a heavy metal found in animal wastes), ciprofloxacin (a common veterinary fluoroquinolone antibiotic), and 4-nitrophenol (4-NP) or 2-chloro-4-nitrophenol (2C-4NP) at μM concentrations and pH = 7.0.

Experiments with 4-NP at varying pH demonstrated that the nitrophenolate form is required for ternary complexation. Solutions also containing Cd, ciprofloxacin, 2,6-dichloro-4-nitrophenol (2,6C-4NP) or 2- chloro-4,6-dinitrophenol (2C-4,6NP) formed insoluble 1:1 charge transfer complexes between ciprofloxacin and either nitrophenol. Charge transfer complexation may be due to the enhanced electrophilicity of these nitrophenols; steric hindrance may also partially explain the observed difference in complex type. For the eight phenols that were tested in this study, a nitro group in the para position appeared to be necessary for formation of the ternary or charge transfer complexes. Experiments to determine the stabilities of the ternary complexes are ongoing. These results are important because they point to an unaddressed reaction pathway available to heavy metals, powerful antibiotics, and toxic phenolic degradation compounds.

Recommended Citation

Weeramantri, Indumini A.. "Identification and Stability of Fluoroquinolone Antibiotic Complexes Involving Heavy Metals, Ciprofloxacin, and Phenolic Degradation Products: Relevance in Ground and Waster Water Systems." Undergraduate Research Symposium, Mankato, MN, April 4, 2011.
http://cornerstone.lib.mnsu.edu/urs/2011/poster-session-B/25