Abstract

Two spectrophotometric methods in visible region have been developed for estimation of ambroxol hydrochloride in bulk drug and in tablets. In method A1 the -NH2 group of ambroxol reacts with sodium nitrite and forms a diazo compound which couples with N- (1-naphthy1)- ethylene diamine dihydrochloride to form a pinkish red chromogen which exhibits maximum absorption at 500 nm against a reagent blank. Method B is based on the reduction of ferric ions in its salt to ferrous ions by the drug, producing a yellowish orange chromogen with absorption maximum at 400 nm against the reagent blank. Beer's law was obeyed in the range of 10 to 50 μg/ml for method A and 40 to 240 μg/ml for method B. The results of analysis have been validated statistically and by recovery studies. The recovery ranged between 100.6 and 100.3% for method A and between 99.6 and 100.2% for method B. This paper describes new, simple and sensitive colourimetric methods for the estimation of ambroxol hydrochloride in bulk drug and pharmaceutical dosage forms.