With Glew-Hildebrand saturation technique

aqueous solubilities of Ofloxacin.Nor floxacin and Pipemidic acid are measured at different temperatures by HPLC and artificial neural network technique

respectively.Given to the solubilities of quinolone medicines

a solubility model is proposed by using chemical engineering thermodynamic theory.This model is veritied by experimental and reference data.A new molecular topological index is proposed with extensive distance atrix

which can describe the molecular structures of hetero-atom

multi-bonds and comp1ex-cycle compounds.Finally

the a mode1 relating solubility to molecular structure is ob tained by using the experimental solubility data of these three kinds of uinolones.Based on this model

the solubilities of nine quinolones

such as Fleroxacin

at 25℃ and 37℃ are predicted and the results are in good agreement with experimental data．