COLORIMETRIC DETERMINATION OF CERTAIN ANTIFUNGALS IN PURE FORMS AND IN THEIR PHARMACEUTICAL FORMULATIONS*

An accurate and sensitive visible spectrophotometric method was developed and validated for the analysis of five antifungal drugs namely; clotrimazole, fluconazole, ketoconazole, miconazole nitrate and tolnaftate in pure as well as in their pharmaceutical dosage forms. This method was based on condensation of any of the cited drug with saturated solution of citric acid in anhydrous acetic anhydride in boiling water bath for about 20–30 min. The produced color was measured spectrophotometrically at 535 nm, after dilution with absolute ethanol. All variables affecting reaction conditions were optimized and the regression analysis of Beer’s plots showed good correlation coefficients (0.9996 - 0.9999) for the previously mentioned drugs in a general concentration range of 0.8–7 μg ml-1 with overall limits of detection and quantitation in the following ranges: 0.039–0.26 μg ml-1 and 0.13–0.87 μg ml-1, respectively. The proposed method has been applied successfully for the analysis of bulk drugs and their dosage forms such as topical powder and solution, oral and vaginal tablets, and topical creams. Overall percentage recoveries in the average range: 94.14–99.02% was obtained with considerable accuracy upon analysis of these dosage forms by the proposed method. No interference could be detected from betamethasone or dexamethosane, encountered excipients and additives. The obtained results have been compared with those obtained from reported and / or official method(s) and proper F- and t- values were observed; indicate no significance difference between the results of the proposed and reported methods. The good percentage recoveries and proper statistical data proved the efficiency of the proposed method for the analysis of the cited drugs in their commercial dosage forms with quite satisfactory precision.