first order ratio derivative method

Two simple, rapid, precise and accurate spectrophotometric methods have been developed for simultaneous analysis of Ibuprofen (IBU) and Famotidine (FAMO) in their combined dosage form. Method A, absorbance correction method involves measurement of amplitudes at 220 nm (for IBU) and 288 nm (for FAMO) in zero derivative spectra. Method B, ratio derivative spectrophotometry, involves division of spectra of IBU by one selected standard spectrum of FAMO and then measuring amplitudes at 234.2 nm in ratio derivative spectra for estimation of IBU. Similarly, spectra of FAMO are divided by one selected standard spectrum of IBU and then amplitudes at 277.8 nm in ratio derivative spectra are measured for estimation of FAMO. Developed methods were validated according to ICH guidelines. The calibration graph follows Beer’s law in the range of 2 to 60 µg/ml for IBU and 3.8 to 4.6 µg/ml for FAMO with R2 value greater than 0.999. Accuracy of all methods was determined by recovery studies and showed % recovery between 98 to 102%. Intraday and Interday precision was checked for both the methods and mean %RSD was found to be less than 2 for these methods. The methods were successfully applied for estimation of IBU and FAMO in marketed formulation.