New Spectrophotometric Methods For The Determination Of Salmeterol Xinafoate
Two simple and sensitive spectrophotometric methods (A and B) in the visible region have been developed for the determination of salmeterol xinafoate (SX) in bulk and in dosage forms. Method A is based on the reaction of SX with hydrochloric acid and sodium nitrite under alkaline conditions to form a stable yellow colored chromogen with absorption maximum of 430 nm and method B is based on the reaction of SX with ferric alum reagent to form a stable blue colored chromogen with the absorption maximum of 620 nm. The color obeyed Beer's law in the concentration range of 0-32 Î¼g/ml for method A and 0-200 Î¼g/ml for method B respectively. When pharmaceutical preparations (Laboratory prepared tablets) were analysed, the results obtained by the proposed methods are in good agreement with the labelled amounts and are comparable with the results obtained using a UV spectrophotometric method. Recovery in both the methods is 98-101%.