Assay of Chloramphenicol in its Pharmaceutical Preparation (eye drop) via Oxidation and Bleaching Color of Neutral Red Dye

Abstract

A simple and rapid spectrophotometric method for the determination of chloramphenicol in its pure form and in its pharmaceutical preparation (eye drop) was suggested. The method involved the use of a new reagent, Neutral red (NR) dye. The method depends on the oxidation of reduced chloramphenicol with an excess amount of N-bromosucinimide (NBS) in an acidic medium, and then the remaining amount of (NBS) was used to bleach the color of the NR dye and measure the absorbance of the residual amount of dye at the wavelength 523 nm which is directly proportional to the concentration of chloramphenicol. All factors that affected the two reactions were studied, and these factors include the type and amount of acid used, the amount of oxidizing agent, the reaction medium, the times required for complete oxidation, and the bleaching time, it was recommended to use the optimal conditions. The limits of Beer's law obeyed from 1 to 8 µg/ml of chloramphenicol with a determination coefficient of 0.9992 and the molar absorptivity was 3.5835 x 104 L.mol-1.cm-1 and Sandell's sensitivity index was 0.009017 µg. cm-2, The value of (LOD) and ‎‏(LOQ) were 0.02374 µg/ml, and 0.07914 µg/ml respectively. The method has been successfully applied for the determination of chloramphenicol in its pharmaceutical preparation (eye drop).