INVESTIGATION OF KETOCONAZOLE-IRON(III) COMPLEX AND ITS SPECTROPHOTOMETRIC DETERMINATION IN PHARMACEUTICAL PREPARATIONS

It has been established that ketoconazole reacts with iron(III) chlori de in the presence of potassium thiocyanate to form a pink complex (2: 1) that is soluble in 1,2-dichloroethane with a maximum absorbance at 510 nm. By application of the methods of Sommer and Job involving non- equimolar solutions, the conditional stability constant (log K-1) of t he complex at the optimum pH of 3.5 and an ionic strength (mu) 0.1 M, was found to be 8.795. The molar absorptivity al 510 nm was 7.75 x 10( 3) 1 mol(-1) cm(-1) at pH 3.5. The validity of Beer's law has been tes ted in the concentration range 5-50 mu g ml(-1) in the organic layer, the relative standard deviation (n = 8) was 0.75-1.46%. The proposed m ethod was found to be suitable for the accurate, simple and rapid anal ysis of ketoconazole in the bulk drug and in tablets.