Sensitive Spectrophotometric Methods for Determination of Non UV Absorbing Ethambutol

Abstract

Two simple and sensitive spectrophotometric methods are described for the quantitative determination of ethambutol. The first method is based on the reaction between dichlorophenol indophenol (DCPIP) and ethambutol to give bluish violet radical ions exhibiting maximum absorption at 640 nm. The second method depends upon the formation of yellow colored ethambutol picrate measurable at 430 nm. Obedience of both chromogens to Beer's law permits the ethambutol determination in pharmaceutical preparation with high accuracy and good reproducibility.

Key Words:

• Ethambutol
• 2,6-Dichlorophenol Indophenol
• Picric Acid
• Pharmaceutical Preparation
• First - Derivative Spectrophotometry