Standardization of the method for estimation of ethambutol in pharmaceutical preparations and biological fluid

A simple column chromatographic method for determination of ethambutol (EMB) in pharmaceutical preparations containing EMB in combination with other anti-TB drugs is presented. The method involved extraction of EMB into an organic solvent. followed by basification and column chromatographic separation on Amberlite CG 50 (100-200 mesh) and elution with suitable eluants and estimation at a wavelength of 270 nm. The assay was linear from 25 to 400 μg/ml. The relative standard deviations of intra and inter day assays were lower than 5%. Ethambutol was recovered from human urine quantitatively and stable for a period of atleast one week in urine stored at-20°C