Determination of Some Fluoroquinolone Antibacterials with DNA-Modified Electrodes and their Oxidation by Potassium Hexacyanoferrate(III)
Date
2006
Authors
Ibrahim Diab Najeeb Abu-Shqair
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Abstract
UV-visible spectroscopic and electrochemical methods were used to study the interaction of some fluoroquinolones with calf-thymus DNA. UV-visible spectroscopy was used to evaluate the binding constants of drug-DNA complexes and to elucidate the nature of binding of of these drugs with DNA. The interaction of the studied fluoroquinolones with DNA was investigated by cyclic voltammetry at a glassy carbon electrode with an irreversible electrochemical equation. The diffusion coefficients of both free and bound fluoroquinolones (Df, Db), the binding constant (K), and the binding site size (s) of fluoroquinolone-DNA complexes were obtained simultaneously by non-linear fit analysis of the experimental data. The results suggested that fluoroquinolones bind to DNA through an electrostatic mode of interaction with partial intercalation.
DNA-modified glassy carbon electrodes were used for the first time as a biosensor for the determination of the studied compounds. Differential-pulse anodic stripping voltammetry was used for investigating different factors that affect the oxidation of the studied fluoroquinolones at the DNA-biosensor. A method was proposed for the determination of ciprofloxacin concentration both in tablets and in a biological fluid (urine). The method was found to be sensitive, accurate, and inexpensive.
Kinetics of osmium tetroxide catalyzed-oxidation of the studied fluoroquinolones by potassium hexacyanoferrate (III) in alkaline medium were studied. The rate was found to be independent on the concentration of hexacyanoferrate (III), and first order with respect to both fluroquinolone and OsO4. An empirical rate law was derived for the reaction, and the effect of various variables on the rate of reaction was studied. Thermodynamic parameters (Ea, ΔH*, ΔS*, ΔG*) were also calculated.
ﺍﻟﻔﻠﻭﺭﻭﻜﻭﻴﻨﻭﻟﻭﻨﺎﺕ ﻤﻥ ﺃﻫﻡ ﺍﻟﻤﻀﺎﺩﺍﺕ ﺍﻟﺤﻴﻭﻴﺔ ﺍﻟﻤﺴﺘﺨﺩﻤﺔ ﻓﻲ ﺍﻷﺩﻭﻴﺔ ﺍﻟﺒﺸﺭﻴﺔ ﻭﺍﻟﺒﻴﻁﺭﻴﺔ ﺍﻟﺘﻲ ﺘﻌﻤل ﻋﻠﻰ ﺘﺜﺒﻴﻁ ﺘﺼﻨﻴﻊ ﺍﻟﺤﻤـﺽ ﺍﻟﻨـﻭﻭﻱ ﺍﻟﺭﺍﻴﺒـﻭﺯﻱ ﺍﻟﻼﺃﻜﺴـﺠﻴﻨﻲ(DNA) ﺍﻟﺨـﺎﺹﺒﺎﻟﺒﻜﺘﻴﺭﻴﺎ. ﻤﻥ ﺍﻷﻤﺜﻠﺔ ﻋﻠﻰ ﻫﺫﻩ ﺍﻟﻤﺠﻤﻭﻋﺔ ﻨﻭﺭﻓﻠﻭﻜﺴﺎﺴﻴﻥ،ﺍﻴﻨﺭﻭﻓﻠﻭﻜﺴﺎﺴﻴﻥ ﻭ ﺴﺒﺭﻭﻓﻠﻭﻜﺴﺎﺴـﻴﻥ ﺍﻟﺫﻱ ﺍﻜﺘﺴﺏ ﺃﻫﻤﻴﺔ ﺨﺎﺼﺔ ﻓﻲ ﻤﻌﺎﻟﺠﺔ ﺃﻋﺭﺍﺽ ﺍﻷﺼﺎﺒﺔ ﺒـﺎﻟﺠﻤﺭﺓ ﺍﻟﺨﺒﻴﺜـﺔ (ﺍﻨﺜـﺭﺍﻜﺱ). ﺇﻻ ﺃﻥ ﺍﻟﻤﻴﻜﺎﻨﻴﻜﻴﺔ ﺍﻟﺘﻲ ﺘﺘﻔﺎﻋل ﺒﻬﺎ ﻫﺫﻩ ﺍﻷﺩﻭﻴﺔ ﻤﻊ DNA ﻻ ﺘﺯﺍل ﻏﻴﺭ ﻤﻔﻬﻭﻤﺔ ﺒﺸﻜل ﻗﺎﻁﻊ ﺤﺘﻰ ﺍﻻﻥ. ﻓﻲ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺘﻡ ﺍﺴﺘﺨﺩﺍﻡ ﻤﻁﻴﺎﻑ ﺍﻷﺸﻌﺔ ﻓﻭﻕ ﺍﻟﺒﻨﻔﺴﺠﻴﺔ ﻭﺍﻟﻤﺭﺌﻴـﺔ ( UV-visible spectroscopy ) ﻭﻜﺫﻟﻙ ﻁﺭﻕ ﻜﻬﺭﻭﻜﻴﻤﻴﺎﺌﻴﺔ ﻟﺩﺭﺍﺴﺔ ﺘﻔﺎﻋل ﻫﺫﻩ ﺍﻟﻤﺭﻜﺒﺎﺕ ﻤﻊ DNA. ﺤﻴﺙ ﺘﻡ ﺍﺴﺘﺨﺩﺍﻡ ﻁﻴﻑ ﺍﻷﺸﻌﺔ ﻓﻭﻕ ﺍﻟﺒﻨﻔﺴـﺠﻴﺔ ﻟﺤﺴـﺎﺏ ﺜﺎﺒـﺕ ﺍﻟﺘـﺭﺍﺒﻁ (binding constsnt, K) ﻭ ﻟﺘﻭﻀﻴﺢ ﻁﺒﻴﻌﺔ ﺍﻟﺘﺭﺍﺒﻁ ﻤﻊ DNA. ﻜﺫﻟﻙ ﺘﻤﺕ ﺩﺭﺍﺴـﺔ ﻫـﺫﺍ ﺍﻟﺘـﺭﺍﺒﻁ ﻷﻭل ﻤـﺭﺓ ﺒﺎﺴـﺘﺨﺩﺍﻡ ﺍﻟﻔﻭﻟﺘﻤﺘﺭﻴﺔ ﺍﻟﺤﻠﻘﻴﺔ ( cyclic voltammetry) ﻋﻠﻰ ﻗﻁﺏ ﺍﻟﻜﺭﺒﻭﻥ ﺍﻟﺯﺠﺎﺠﻲ ( glassy carbon electrode) ﺒﺎﺴﺘﺨﺩﺍﻡ ﻤﻌﺎﺩﻟﺔ ﻜﻬﺭﻭﻜﻴﻤﻴﺎﺌﻴﺔ ﺨﺎﺼﺔ، ﺤﻴﺙ ﺘﻡ ﺤﺴﺎﺏ ﻤﻌﺎﻤل ﺍﻨﺘﺸـﺎﺭ ﻜـل ﻤـﻥ Db) ﻜﻤﺎ ﺘﻡ ﺤﺴﺎﺏ ﺤﺠﻡ ﻤﻭﻗﻊ ﺍﻟﺘرﺍﺒﻁ f ﻭ ﺍﻟﻤﺭﺘﺒﻁﺔ ﻤﻊ DNA ( ﺍﻟﻔﻠﻭﺭﻭﻜﻭﻴﻨﻭﻟﻭﻨﺎﺕ ﺍﻟﺤﺭﺓ( D) (binding sites size, s) ﻟﻠﻤﻌﻘﺩ ﺍﻟﻨﺎﺘﺞ ﻤﻥ ﺍﺭﺘﺒﺎﻁ ﻫﺫﻩ ﺍﻟﻤﺭﻜﺒـﺎﺕ ﻤـﻊ FQ-DNA ) DNA complex) ﻭﺜﺎﺒﺕ ﺍﻟﺘﺭﺍﺒﻁ (K) ﻤﻥ ﺨﻼل ﺘﻁﺒﻴﻕ ﺍﻟﻤﻌﺎﺩﻟﺔ ﺍﻟﻜﻬﺭﻭﻜﻴﻤﻴﺎﺌﻴﺔ ﻋﻠﻰ ﻨﺘـﺎﺌﺞ ﺍﻟﻌﻤﻠﻴـﺔ ﺒﺎﺴﺘﺨﺩﺍﻡ ﺒﺭﻨﺎﻤﺞOrigin. ﺒﻨﺎﺀ ﻋﻠﻰ ﺍﻟﻨﺘﺎﺌﺞ ﺍﻟﻤﺴﺘﺨﺭﺠﺔ ﻤﻥ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺘﻡ ﺍﻗﺘﺭﺍﺡ ﺍﻟﻴﺔ ﺍﻟﺘـﺭﺍﺒﻁ (lectrostatic binding with partial intercalation ) ﺍﻟﺠﺯﺌﻲ ﺍﻟﺘﺩﺍﺨل ﻤﻊ ﺍﻟﻜﻬﺭﻭﺴﺘﺎﺘﻴﻜﻲ ﻟﻭﺼﻑ ﺍﺭﺘﺒﺎﻁ ﻫﺫﻩ ﺍﻟﻤﺭﻜﺒﺎﺕ ﻤﻊDNA.
ﺍﻟﻔﻠﻭﺭﻭﻜﻭﻴﻨﻭﻟﻭﻨﺎﺕ ﻤﻥ ﺃﻫﻡ ﺍﻟﻤﻀﺎﺩﺍﺕ ﺍﻟﺤﻴﻭﻴﺔ ﺍﻟﻤﺴﺘﺨﺩﻤﺔ ﻓﻲ ﺍﻷﺩﻭﻴﺔ ﺍﻟﺒﺸﺭﻴﺔ ﻭﺍﻟﺒﻴﻁﺭﻴﺔ ﺍﻟﺘﻲ ﺘﻌﻤل ﻋﻠﻰ ﺘﺜﺒﻴﻁ ﺘﺼﻨﻴﻊ ﺍﻟﺤﻤـﺽ ﺍﻟﻨـﻭﻭﻱ ﺍﻟﺭﺍﻴﺒـﻭﺯﻱ ﺍﻟﻼﺃﻜﺴـﺠﻴﻨﻲ(DNA) ﺍﻟﺨـﺎﺹﺒﺎﻟﺒﻜﺘﻴﺭﻴﺎ. ﻤﻥ ﺍﻷﻤﺜﻠﺔ ﻋﻠﻰ ﻫﺫﻩ ﺍﻟﻤﺠﻤﻭﻋﺔ ﻨﻭﺭﻓﻠﻭﻜﺴﺎﺴﻴﻥ،ﺍﻴﻨﺭﻭﻓﻠﻭﻜﺴﺎﺴﻴﻥ ﻭ ﺴﺒﺭﻭﻓﻠﻭﻜﺴﺎﺴـﻴﻥ ﺍﻟﺫﻱ ﺍﻜﺘﺴﺏ ﺃﻫﻤﻴﺔ ﺨﺎﺼﺔ ﻓﻲ ﻤﻌﺎﻟﺠﺔ ﺃﻋﺭﺍﺽ ﺍﻷﺼﺎﺒﺔ ﺒـﺎﻟﺠﻤﺭﺓ ﺍﻟﺨﺒﻴﺜـﺔ (ﺍﻨﺜـﺭﺍﻜﺱ). ﺇﻻ ﺃﻥ ﺍﻟﻤﻴﻜﺎﻨﻴﻜﻴﺔ ﺍﻟﺘﻲ ﺘﺘﻔﺎﻋل ﺒﻬﺎ ﻫﺫﻩ ﺍﻷﺩﻭﻴﺔ ﻤﻊ DNA ﻻ ﺘﺯﺍل ﻏﻴﺭ ﻤﻔﻬﻭﻤﺔ ﺒﺸﻜل ﻗﺎﻁﻊ ﺤﺘﻰ ﺍﻻﻥ. ﻓﻲ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺘﻡ ﺍﺴﺘﺨﺩﺍﻡ ﻤﻁﻴﺎﻑ ﺍﻷﺸﻌﺔ ﻓﻭﻕ ﺍﻟﺒﻨﻔﺴﺠﻴﺔ ﻭﺍﻟﻤﺭﺌﻴـﺔ ( UV-visible spectroscopy ) ﻭﻜﺫﻟﻙ ﻁﺭﻕ ﻜﻬﺭﻭﻜﻴﻤﻴﺎﺌﻴﺔ ﻟﺩﺭﺍﺴﺔ ﺘﻔﺎﻋل ﻫﺫﻩ ﺍﻟﻤﺭﻜﺒﺎﺕ ﻤﻊ DNA. ﺤﻴﺙ ﺘﻡ ﺍﺴﺘﺨﺩﺍﻡ ﻁﻴﻑ ﺍﻷﺸﻌﺔ ﻓﻭﻕ ﺍﻟﺒﻨﻔﺴـﺠﻴﺔ ﻟﺤﺴـﺎﺏ ﺜﺎﺒـﺕ ﺍﻟﺘـﺭﺍﺒﻁ (binding constsnt, K) ﻭ ﻟﺘﻭﻀﻴﺢ ﻁﺒﻴﻌﺔ ﺍﻟﺘﺭﺍﺒﻁ ﻤﻊ DNA. ﻜﺫﻟﻙ ﺘﻤﺕ ﺩﺭﺍﺴـﺔ ﻫـﺫﺍ ﺍﻟﺘـﺭﺍﺒﻁ ﻷﻭل ﻤـﺭﺓ ﺒﺎﺴـﺘﺨﺩﺍﻡ ﺍﻟﻔﻭﻟﺘﻤﺘﺭﻴﺔ ﺍﻟﺤﻠﻘﻴﺔ ( cyclic voltammetry) ﻋﻠﻰ ﻗﻁﺏ ﺍﻟﻜﺭﺒﻭﻥ ﺍﻟﺯﺠﺎﺠﻲ ( glassy carbon electrode) ﺒﺎﺴﺘﺨﺩﺍﻡ ﻤﻌﺎﺩﻟﺔ ﻜﻬﺭﻭﻜﻴﻤﻴﺎﺌﻴﺔ ﺨﺎﺼﺔ، ﺤﻴﺙ ﺘﻡ ﺤﺴﺎﺏ ﻤﻌﺎﻤل ﺍﻨﺘﺸـﺎﺭ ﻜـل ﻤـﻥ Db) ﻜﻤﺎ ﺘﻡ ﺤﺴﺎﺏ ﺤﺠﻡ ﻤﻭﻗﻊ ﺍﻟﺘرﺍﺒﻁ f ﻭ ﺍﻟﻤﺭﺘﺒﻁﺔ ﻤﻊ DNA ( ﺍﻟﻔﻠﻭﺭﻭﻜﻭﻴﻨﻭﻟﻭﻨﺎﺕ ﺍﻟﺤﺭﺓ( D) (binding sites size, s) ﻟﻠﻤﻌﻘﺩ ﺍﻟﻨﺎﺘﺞ ﻤﻥ ﺍﺭﺘﺒﺎﻁ ﻫﺫﻩ ﺍﻟﻤﺭﻜﺒـﺎﺕ ﻤـﻊ FQ-DNA ) DNA complex) ﻭﺜﺎﺒﺕ ﺍﻟﺘﺭﺍﺒﻁ (K) ﻤﻥ ﺨﻼل ﺘﻁﺒﻴﻕ ﺍﻟﻤﻌﺎﺩﻟﺔ ﺍﻟﻜﻬﺭﻭﻜﻴﻤﻴﺎﺌﻴﺔ ﻋﻠﻰ ﻨﺘـﺎﺌﺞ ﺍﻟﻌﻤﻠﻴـﺔ ﺒﺎﺴﺘﺨﺩﺍﻡ ﺒﺭﻨﺎﻤﺞOrigin. ﺒﻨﺎﺀ ﻋﻠﻰ ﺍﻟﻨﺘﺎﺌﺞ ﺍﻟﻤﺴﺘﺨﺭﺠﺔ ﻤﻥ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﺘﻡ ﺍﻗﺘﺭﺍﺡ ﺍﻟﻴﺔ ﺍﻟﺘـﺭﺍﺒﻁ (lectrostatic binding with partial intercalation ) ﺍﻟﺠﺯﺌﻲ ﺍﻟﺘﺩﺍﺨل ﻤﻊ ﺍﻟﻜﻬﺭﻭﺴﺘﺎﺘﻴﻜﻲ ﻟﻭﺼﻑ ﺍﺭﺘﺒﺎﻁ ﻫﺫﻩ ﺍﻟﻤﺭﻜﺒﺎﺕ ﻤﻊDNA.