Nina Alizadeh - Department of Chemistry, University of Guilan, Rasht ۴۱۳۳۵-۱۹۱۴, Iran
Zahra Rezakhani

The reactions of picric acid and bromothymol blue with three important antifungal drugs containing an imidazole ring ketoconazole (KC) and clotrimazole(CT) and fluconazole (FC) have been studied for the development of simple, rapid, sensitive an extractivespectrophotometric method for determining the concentration of these drugs. This method is based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug andsulphonphthalein acid dyes, namely; bromothymol blue (BCG) in phosphate buffer of pH =3 and picric acid (PA) in citrate buffer of pH=2.5. The formedcomplexes were extracted with chloroform and measured at 410 and 415nm for KC, at 410 and 413nm for CT and at 373 and 415nm for FC using PAand BTB, respectively. The analytical parameters and their effects on the reported systems are investigated. Beer’s law was obeyed in the range 1-60 , 1-58 and3-60 μg/ mL with PA and 3-55, 2-50 and 5-55 μg/ mL with BTB for CT, KC and FC, respectively. The composition of the ion pairs was found 1:1 by mole ratio and job′ s method in all cases. The proposed methods have been applied successfully forthe analysis of the studied drugs in pure forms andpharmaceutical formulations.The results are in good agreement with those obtained by official methods