Correlation of the Solubility Parameter and Antibacterial Activity of Moxifloxacin

An attempt is made to determine the solubility parameter of moxifloxacin HCl and to establish the correlation between solubility parameter and drug properties using different methods given in the literature. The solubility parameter of the drug was calculated by Hoyrsquos molar attraction constants and peak solubility technique. Saturation solubility values of the drug were determined in various solvent blends having solubility parameter values ranging from 8.9 to 20.7 H. The solubility parameter of drug was 11.46 H and 11.67 H from Hoyrsquos method and peak solubility method respectively. Minimum inhibitory concentration MIC and Zone of inhibition ZOI of the drug for E. coli S. aureus and S. Paratyphi-A were determined. MIC was maximum for the drug in solvent system having the solubility parameter nearer to that of the drug. Minimum ZOI was observed for the drug in solvent system having the solubility parameter nearer to the drug solubility parameter. Transport studies revealed that the drug rejection from the solvent blends was dependent on its solubility parameter. Correlation was observed between the solubility parameter of the drug and the properties namely solubility diffusion of the drug MIC and antibacterial activity. Thus the solubility parameter of the drug can be correlated with the antibacterial activity of drug which can be used as a model.