Studies On The Antagonistic Action Between Fluoroquinolones And Chloramphenicol By Spectroscopy

Protein is one of the important organic substances in the life; it has other functions, such as catalytic, regulation, transport and carrier drugs. It plays an important role in the life activity. Serum albumin is the most abundant carrier protein in blood plasma. Therefore, it has been an intensively research protein of clinical and chemistry research, especially researchs on the interaction between drugs and BSA have been intensively reported in this filed. This paper has carried on the study about the mechanism between small drug molecules and serum albumin by spectroscopy. This paper divided into five chapters:Chapter one: This section actuality of interaction between small molecules with serum albumin and the progress of fluorescence spectroscopy in recent years has been reviewed. Based on this, the research significance and methods for study of the reaction mechanism between small molecules with protein were established, with 65 literatures quoted.Chapter two: Studies on the antagonistic action between Chloramphenicol and Fluoroquinolones with presence of bovine serum albumin by fluorescence spectroscopy. Chloramphenicol (CHL) and Fluoroquinolone drugs (FQNS) like ofloxacin (OFLX), lomefloxacin (LMX) and ciprofloxacin (CPFX) can all quench the fluorescence of bovine serum albumin (BSA) in the aqueous solution of pH=7.40. This quenching effect became more significant when CHL and quinolone drugs coexist. Based on this, further studies on the interactions between CHL and quinolone drugs using fluorescence spectrum were established. The results showed that the interaction between the drugs would increase the binding constant and binding stability of the drug and protein, thus reducing the amount of drugs transported to their targets. Therefore, free drug concentration at targets would decrease, reducing the efficacy of the drugs. It indicated that there exists antagonistic action between drugs. The results also showed that the quenching mechanism of BSA by the drugs is a static procedure. The number of binding sites is 1 in various systems. Due to the existence of the antagonistic action between drugs, the binding distance r is reduced. Studies utilizing synchronous spectra showed that the antagonistic action between the drugs would affect the conformation of BSA, making protein molecules extend and hydrophobic decrease. The order of antagonistic action between CHL and quinolone drugs is: CPFX>OFLX>LMX with presence of BSA.Chapter three: Application of fluorescence spectroscopy to a study on the antagonism between Chloramphenicol and Sarafloxacin. Both chloramphenicol (CHL) and sarafloxacin (SLFX) can quench the fluorescence from bovine serum albumin (BSA). The fluorescence will quench to a larger degree when the two drugs coexist. We thus studied the antagonism between SLFX and CHL using fluorescence spectroscopy. We proved that the antagonism between the drugs increases the binding stability between drug and protein. At the same time, a reduction of the free drug's concentration will reduce the effect of the drugs. Results show that the quenching mechanism of the combination for bovine serum albumin and drugs is a static procedure. The number of binding sites is 1. Based on the theory of F?rester energy transfer spectroscopy, the binding distance r between drugs and bovine serum albumin was obtained. Because of the existence of antagonism between the drugs, the correlation coefficient and binding distance are reduced. Synchronous spectra were obtained, which showed the effect of this antagonism between the drugs on the conformation of BSA. The protein molecules are extended and their hydrophobic nature is reduced.Chapter four: Studies on the antagonistic action between Chloramphenicol and Norfloxacin by fluorescence spectrum. The reaction between Norfloxacin-Chloramphenicol and bovine serum albumin in aqueous solution is studied by fluorescence spectroscopy and UV-absorption spectroscopy. These two drugs can both quench the fluorescence of BSA. Based on this, further studies on the interactions between Chloramphenicol and Norfloxacin using fluorescence spectrum are established. The results showed that the interaction between the drugs would increase the binding constant and binding stability of the drug and protein, thus reducing the free drug concentration. The results also showed that the quenching mechanism of BSA by the drugs is a static procedure. The number of binding sites about 1. Based on the theory of F?rester energy transfer spectroscopy, the binding distance r between drugs and bovine serum albumin was obtained. Studies utilizing synchronous spectra showed that the interaction between the drugs would affect the conformation of BSA and the distance between molecules. Chapter five: Study of the fluorescence quenching mechanism of bovine serum albumin with prescence of chloramphenicol and enrofloxacin. The quenching mechanism of bovine serum albumin with presence of chloramphenicol (CHL) and enrofloxacin (EFLX) were studied in the aqueous solution of pH=7.40. This paper obtained the binding constant, the number of binding sites and the binding distance. The results showed that the quenching mechanism of BSA by the drugs is a static procedure. The results also showed that the interaction between the drugs would increase the binding stability of the drug and protein, thus reducing the amount of drugs transported to their targets. Therefore, free drug concentration at targets would decrease, reducing the efficacy of the drugs. The number of binding sites is 1. Accroding to the theory of F?rester energy transfer spectroscopy, the binding distance r between drugs and bovine serum albumin was obtained. Synchronous spectra showed that the interaction between the drugs would affect the conformation of BSA.