Derivative Spectrophotometric Method for Determination of Losartan in Pharmaceutical Formulations

Losartan, a highly effective blood pressure lowering agent, has been widely used for the treatment of hypertension. A fast and reliable method for the determination of losartan was highly desirable to support formulation screening and quality control. A first derivative UV spectroscopic method was developed for determination of losartan in the tablet dosage form. The first derivative spectrum recorded between 220 and 320 nm, and a zero-crossing technique for first derivative measurement at 232.5 nm was selected. It is found that the selectivity and sensitivity of method to be in desirable range. In comparison with the direct UV method, the first derivative UV spectroscopy has a definite through without any interference from UV absorbing excipients. This method is also fast and economical in comparison to the more time-consuming HPLC method regularly used for formulation screening and quality control and can be used routinely by any laboratory possessing a spectrophotometer with a derivative accessory. The linear concentration ranges were 2-50 ?g/mL, (Dl = -0.0159C - 0.0056, r =0.9994, n=6). Between days CV% 2.9, within day CV% 2.1, analytical recovery close to 98.1 % shows the suitability of the method for determination in quality control.