Simultaneous spectrophotometric determination of diuretics by using multivariate calibration methods

The wavelength range and number of factors used in partial least-squares (P LS) calibration for the resolution of the dihydralazine (DHZ)-hydrochloroth iazide (HCT) binary mixture and the dihydralazine-hpdrochlorothiazide-reser pine ternary mixture were optimized in terms of the relative standard error (R.S.E.) and relative mean standard error (R.M.S.E.). Under the optimum co nditions thus established, synthetic mixtures of the analytes can be resolv ed with errors and relative standard deviations (R.S.D) less than 4.5 and 1 .0%, respectively. The ensuing method, which was validated by comparison wi th high performance liquid chromatography (HPLC), also gives good results w ith real samples (pharmaceutical preparations). (C) 2001 Elsevier Science B .V. All rights reserved.