Simple spectrophotometric method for estimation of drugs using chloraminet and indigo caramine dye couple

The five drugs viz., GEM, PHE, TRD, IMT, VRP were estimated using a simple, specific, accurate and precise UV–visible spectrophotometric method. These methods involve the addition of a known nexcess of Chloramine-T to the drugs in acid medium followed by estimation of residual Chloramine-T by reacting with a fixed amount of Indigo caramine dye and measuring the absorbance of the dye at 608 nm. The calibration curves obeyed Beer’s law over the concentration range of 3.0,5.5,6.5 μg mL-1 of GEM; 2.5,3.69,5.01 μg mL-1 of PHE ; 2.0,3.5,7.5 μg mL-1 of TRD; 3.0,4.5,7.0 μg mL- 1 of IMT; and 4.2,5.5,7.0 μg mL-1 of VRP were chosen. The methods that are developed were found to be suitable for the estimation of these drugs in bulk and their formulations. Several parameters such as linearity, accuracy, and precision, Limit of detection and Limit of quantification were considered for the analysis of results of the drugs and their corresponding validation were carried out statistically.