Spectrophotometric and spectrofluorimetric determination of famotidine and ranitidine using 1,4-benzoquinone reagent

Spectrophotometric and spectrofluorimetric methods were adopted for the analysis of Famotidine and Ranitidine depending on their reaction with 1,4 Benzoquinone reagent at pH 5.2 and 5.6, respectively. The absorbances of the resulting condensation products were measured at 502 and 508 nm for Famotidine and Ranitidine, respectively. Concentrations adhering to Beer's law were from 40-160 mu g.ml(-1) for Famotidine and from 20-100 mu g.ml(-1) for Ranitidine. Furthermore the resulting condensation products exhibited fluorescence at 665 nm when excited at 290 nn and the calibration graphs were rectilinear from 0.4-1.4 mu g.ml(-1) for Famotidine and from 0.21 mu g.ml(-1) for Ranitidine. Different parameters affecting these reactions were thoroughly studied. Also these methods were applied to the pharmaceutical preparations and the results were satisfactory. The validities of the methods were ascertained by the standard addition technique revealing fine results in consideration to the mean recovery percent and standard deviation. The spectrofluorimetric method was a hundred times more sensitive then the spectrophotometric method. The proposed methods were sensitive, accurate, and precise as statistically compared with the official methods of analysis of Famotidine and Ranitidine.