Interaction Of Levofloxacin Lactate With Surfactants

We synthesized series of new quaternary cationic surfactants,the interactions of Levofloxacin lactate with four kinds of cationic surfactants, N-dodecyl-hydroxyl-dimethyl ammonium bromide,N-dodecyl-dihydroxyl-methyl ammonium bromide,N-tetradecyl-hydroxyl-dimethyl ammonium bromide, N-tetradecyl-dihydroxyl-methyl ammonium bromide were studied in three different solutions(5%Glucose,0.9%NaC1,0.05mol·L^-1Tris-HCl)by using UV-Vis spectroscopy.In the presence of different concentrations of surfactants,the UV-Vis absorption spectra of Levofloxacin lactate changed obviously,absorption intensity of the solution increases with the increase of the concentration of surfactants.No obvious red shift or blue shift of absorptions were observed in the same solution.When Levofloxacin lactate was in three different solutions,the maximum of absorption wavelength got red shift from 287nm to 292nm with the increase of acidity of the solution.The same surfactant in three different solutions,the order from strong to weak interaction is 5%Glucose,0.9%NaC1,0.05mol·L^-1Tris-HCl.The equilibrium constants were calculated using Benesi-Hildebrand equation from the experimental absorbance,linear plots between D_T/△A and 1/C_M obtained in all cases studied indicated that binding of Levofloxacin lactate to micelles is in the form of a 1:1 complex.It was found that the longer the hydrophobic chains,the stronger interaction with Levofloxacin lactate.It can be concluded that the interaction of Levofloxacin lactate with surfactants from strong to weak follows the order: N-tetradecyl-hydroxyl-dimethyl ammonium bromide,N-tetradecyl-dihydroxyl-methyl ammonium bromide,N-dodecyl-hydroxyl-dimethyl ammonium bromide, N-dodecyl-dihydroxyl-methyl ammonium bromide.