Simultaneous estimation of ramipril and metoprolol tartrate in combined dosage forms

Abstract

Four new analytical methods were developed based on the simultaneous estimation of drugs in a binary mixture without prior separation. In simultaneous equation method, the drugs were determined by using the absorbance values of ramipril and metoprolol at selected wavelengths, viz. 205 nm and 222.5 nm respectively. The second method depends on the application of area under the curve at selected wavelength range, 200 to 210 nm and 217.5 to 227.5 nm for ramipril and metoprolol tartrate respectively, the linearity range for both the drugs were 10-20 μg/ml. Third method is based on the determination of graphical absorbance ratio at two selected wavelengths; one being the isoabsorptive point for the drugs (216.5 nm) and the other being the absorption maximum of metoprolol (222.5 nm), in this method both the drugs obeyed the Beer-Lambert's law in the concentration range of 16-24 μg/ml. The fourth method is based on the derivative spectrophotometric method at zero crossing wavelengths. These methods are simple, accurate, and rapid, and they require no preliminary separation and can therefore be used for routine analysis of both drugs in quality control laboratories.