SIMULTANEOUS DETERMINATION OF NEBIVOLOL HCL AND VALSARTAN IN SOLID DOSAGE FORM BY SPECTROPHOTOMETRIC AND RP-HPLC METHOD

A simple high-performance liquid chromatography RP-HPLC and two reproducible ultraviolet spectrophotometric methods were developed and validated for the estimation of nebivolol HCl and valsartan simultaneously in combined pharmaceutical solid dosage form. The wavelength fixed for spectrophotometric measurement of valsartan at 246.6 nm, nebivolol HCl at 280.2 nm for the simultaneous equation and for the Q-analysis measurement the two wavelengths fixed are 246.6 nm and 275.0 nm. The linearity obtained for nebivolol HCl in the range of 0.5-2.5 mu g/ml and 5-25 mu g/ml for valsartan by spectrophotometric method. The nebivolol HCl and valsartan were analyzed by HPLC using reverse phase C-18 column (25 cm x 4.6 mm i.d., 5 mu m particle size), by isocratic mobile phase consisted of 50mM ammonium acetate buffer adjusted to pH 3.5 and acetonitrile (30: 70 v/v), at a flow rate of 0.8 ml/min in the detection wavelength of 275 nm. The loratidine was used as an internal standard. The linearity and range of nebivolol HCl are 2-12 mu g/ml and 5-30 mu g/ml for valsartan by HPLC method. The correlation coefficients for all the three methods obtained were >= 0.998. The limit of detection and limit of quantification for nebivolol HCl and valsartan were found to be 12 ng/ml and 38 ng/ml, 32 ng/ml and 95 ng/ml respectively. The accuracy of these methods evaluated by recovery measurements and good recovery results obtained from 98.28% to 102.25% for all the methods and the relative standard deviation of below 3% were achieved.