Determination Of Active Ingredients And Component Analysis Of Levofloxacin Hydrochloride Injection By Coulometric Titration

The paper was consisted of three parts,the first one was to determinate the dissociation constant of levofloxacin hydrocloride by potentiometric titration,to provide a theoretical basis for further research,the second one was to obtain the determination of active ingredients of levofloxacin hydrochloride injection by direct coulometric titration,to provide a method for rapid determination of the quality control of production,in the third part,the improved coulometric titration method was applied to analysis and determinate the components of levofloxacin hydrochloride injection simultaneously,to provide more information for industrial production,clinical medicine.The potentiometric titration was used for the determination of dissociation constant of levofloxacin hydrochloride with the method of generating function.According to the principle of determination of acid dissociation constant of pH titration,the linear equations was employed to calculate the dissociation constants of levofloxacin hydrochloride with better accuracy and reliability by the deformation of Bjerrum generating function to creen and piecewise regression analysis the experimental data.The first dissociation constant of levofloxacin was 6.08,and the second one was 8.25.The determination results were consistent with other methods.The rapid determination of effective content of levofloxacin hydrochloride has failed to solve,so the paper proposed that coulometric titration applied to determinate the effective composition content of levofloxacin with the merity of simplicity,convenience,accuracy,low cost and high degree of automation.The whole process can be completed automatically about 5 minutes,and the results showed that the determination of 4 different batches of levofloxacin in the levofloxacin hydrochloride injection were accorded with the marked value,the relative standard deviation was less than 0.4%,and the relative amount of mark were between 90~110%,which was in accordance with the quality control index of levofloxacine hydrochloride injection.In order to analysis the component form,the determination of component content and effective components in levofloxacin hydrochloride injection,a new method was developed,which was to add accurate excess hydrochloric acid standard solution to injection,and then mixed solution was reacted with the generated OH~-in 1mol/L KCl solution.the components and their combination forms of levofloxacin hydrochloride injection were obtained according to the electrolysis time,and the determination of each component and the effective components of levofloxacin was calculated by the derived formula.The determination results showed that four different batches of levofloxacin hydrochloride injection were consisted of levofloxacin hydrochloride and free levofloxacin,and levofloxacin hydrochloride was the main form with the free levofloxacin as the secondary form(mole ratio was at least 4%,the highest reached 6.2%);the content of effective components of levofloxacin were in full compliance with the quality requirements of production.The study provide a detailed and comprehensive reference data for industrial production,clinical medicine,especially the precise medical research.