COLORIMETRIC ASSAY OF HEXAMETHYLENETETRAMINE

Document Type : Original Article

Authors

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Assiut University, Assiut, Egypt

Abstract

Two photometric procedures are described for the determination of hexamethylenetetramine, free and in pharmaceutical preparation. The two methods are based on color formation by the ammonia released after the hydrolysis of hexamethylenetetramine. In the first method sodium-l,2 naphthoquinone-4-sulphonate reagent was added to the hydrolyzed hexamine sample, after adjustment of the pH of the solution to 9.3, when excess of reagent was eliminated, pink color appeared that was measured at 495 nm (e= 8.6 x l03).
Ninhydrin was applied, in the second proposed method, to the hydrolyzed sample of hexamethylenetetramine after adjustment of the solution pH to 6.5. The color produced had its maximum absorbance at 565 nm with high intensity (e= 1.2 x l04).
Beer's law was obeyed in the range of concentration of 2-20 mcg of hexamine per ml with standard deviation of ± 0.66 and 2-30 mcg/ml with SD± 0.85 in the case of the first and the second methods respectively. The two methods were applied successfully to the analysis of commercially available hexamethylenetetramine tablets.