RESUMEN
Two analytical methods have been developed for simultaneous quantification of bisoprolol fumarate and hydrochlorothiazide in combined pharmaceutical dosage form using spectrophotometer. Excellent simplicity, accuracy, precision and economy were achieved by the assay. The 'method I' was based upon 'simultaneous equations' whereas the 'method II' was based upon 'multicomponent mode of analysis' of the instrument. For both these methods, 0.1 N NaOH was used as solvent. In this solvent, bisoprolol fumarate showed absorbance at 224 nm and hydrochlorothiazide at 273 nm. Linearity lies in the concentration range of 3 - 21 microg/ml for bisoprolol fumarate and 3 - 18 microg/ml for hydrochlorothiazide. The methods were validated statistically and by recovery studies