The interaction of hemin with chloroquine, quinine and quinldine W M hvestigeted in 50% mter-PmPYlme glycol mixture at The data be into a model consistent with the formation of a 1 : 1 complex between the reacting partners. In d t h chloroquine and q*e, and the binding ~0-a were pH&pendent. Moreover, it w~ proved that the water-propyiene g1yco1 mixture is well suitable to the study of the systems containing hemin and quinoline--drugs* between hemin and quinoline drug in aqueous medium. This medium, however, presents some limitations in resoluble in alkaline aqueous solution, whereas quinoline the indicated that complexed more compounds are soluble in acidic aqueous solution. A stable state of hemin in neutral or weakly acidic aqueous solution Can not be achieved because of its tendency to dimerize. As a result, nonconsistent stoichiometries of hemin-quinoline complexes in aqueous solution, such as 2: 1, 4: 1 and 7 : 1 complexes, were reported .am21 There-PH=9* 8-19 7.4 and 6.8 * * ~P h o~m e~c method* gard to the solubility of the reacting partners. Hemin is with qa&e