Simultaneous determination of fosinopril and hydrochlorothiazide in tablets by derivative spectrophotometric and high-performance liquid chromatographic methods

Fourth derivative UV-spectrophotometric and high-performance liquid chromat ographic (HPLC) methods for simultaneous determination of fosinopril and hy drochlorothiazide in tablets have been developed. Standard solutions were m easured at zero crossing wavelengths of 217.7 and 227.9 nm for fosinopril a nd hydrochlorothiazide, respectively, by fourth derivative spectrophotometr ic method. Calibration curves were constructed by plotting d(4)A/d lambda ( 4) values at selected wavelengths against concentrations. HPLC analyses wer e carried out on C-18 column with gradient elution by using 10 mM H3PO4 and CH3CN as mobile phase. Benazepril was used as internal standard and the su bstances were detected at 215 nm. Commercially available tablets containing 20 mg fosinopril and 12.5 mg hydrochlorothiazide were analysed by fourth d erivative spectrophotometric and HPLC methods. The results were compared st atistically at 95% confidence level with each other. There was no significa nt difference between the mean percentage recoveries and precision of the t wo methods. (C) 2001 Elsevier Science B.V. All rights reserved.