APPLICATION OF ALIZARINE DERIVATIVES AS CHROMOGENIC REAGENTS FOR THE SPECTROPHOTOMETRIC DETERMINATION OF SOME SULFA DRUGS

A spectrophotometric procedure for the determination of six pharmaceutical sulfonamides containing a primary aromatic amino group using alizarine (I), alizarine blue (II), alizarine red (III), and quinalizarine (IV), that offers advantages of simplicity, rapidity, sensitivity, precision, and stability, has been developed. The proposed method is based on the formation of colored products with the chromogenic reagents (I-IV). A linear correlation was found between absorbance at lambda(max) and the concentration. For more accurate results, Ringbom optimum concentration ranges are evaluated. The molar absorptivities (epsilon), absorptivities (a), and Sandell sensitivities for all sulfonamides derivatives with the chromogenic reagents tested were calculated. The procedures developed are applied for bulk sulfa drugs and some of their dosage forms. (C) 1995 Academic Press, Inc.