pH对诺氟沙星与BSA之间结合常数的影响

采用毛细管区带电泳法，通过测定在不同pH值、不同牛血清白蛋白浓度的缓冲溶液条件下药物迁移时间的变化，计算出了pH分别为6．8、7．4和8．0时诺氟沙星与牛血清白蛋白相互作用的结合常数，其值分别为6．17×10^4L／mol、7．19×10^4L／mol、4．61×10^4L／mol。结果显示：当pH=7．4时结合常数值最大，当pH增大或减小时，结合常数值均表现出明显的下降趋势。探讨pH对结合常数的影响规律，对于进一步阐明药物作用机理具有较强的理论意义。

Influence of pH value on interactions between norfloxacin and bovine serum albumin

With capillary zone electrophoresis, the interactions between norfloxacin and bovine serum albumin （BSA） Were studied. The migration behaviors of norfloxacin was investigated in a series of running buffers containing different concentrations of BSA. When pH values of the running buffers are 6.8, 7.4 and 8.0 respectively, the binding constants（Kb） of norfloxacin and BSA are 6.17 ×10^4 L/mol, 7. 19 × 10^4 L/mol and 4.61 × 10^4 L/mol correspondingly. Results shows as follows. （ 1 ） pH value has great influence upon the interactions between norfloxacin and BSA; （2） Kb of norfloxacin and BSA gets the maximum when pH value is 7.4 , （3） Kb decreases gradually when pH value is 6.8 or 8.0. The binding type and site between norfloxacin and BSA were investigated in detail. Studying the influence＇of pH values on binding constants is conducive to the research on the pharmacokinetic mechanism of norfloxacin.