OMRAN, A. (2007). SIMULTANEOUS DETERMINATION OF HYDROCHLOROTHIAZIDE AND METHYLDOPA IN TABLETS USING FIRST DERIVATIVE SPECTROPHOTOMETRY AND PLS. Al-Azhar Bulletin of Science, 18(Issue 2-A), 113-126. doi: 10.21608/absb.2007.11123
AHMED A. OMRAN. "SIMULTANEOUS DETERMINATION OF HYDROCHLOROTHIAZIDE AND METHYLDOPA IN TABLETS USING FIRST DERIVATIVE SPECTROPHOTOMETRY AND PLS". Al-Azhar Bulletin of Science, 18, Issue 2-A, 2007, 113-126. doi: 10.21608/absb.2007.11123
OMRAN, A. (2007). 'SIMULTANEOUS DETERMINATION OF HYDROCHLOROTHIAZIDE AND METHYLDOPA IN TABLETS USING FIRST DERIVATIVE SPECTROPHOTOMETRY AND PLS', Al-Azhar Bulletin of Science, 18(Issue 2-A), pp. 113-126. doi: 10.21608/absb.2007.11123
OMRAN, A. SIMULTANEOUS DETERMINATION OF HYDROCHLOROTHIAZIDE AND METHYLDOPA IN TABLETS USING FIRST DERIVATIVE SPECTROPHOTOMETRY AND PLS. Al-Azhar Bulletin of Science, 2007; 18(Issue 2-A): 113-126. doi: 10.21608/absb.2007.11123
SIMULTANEOUS DETERMINATION OF HYDROCHLOROTHIAZIDE AND METHYLDOPA IN TABLETS USING FIRST DERIVATIVE SPECTROPHOTOMETRY AND PLS
Chemistry Department, Faculty of Science, Al-Azhar University, Assiut 71524, Egypt
Abstract
Two new analytical methods are described as convenient and useful alternatives for simultaneous determination of hydrochlorothiazide (HCTZ) and methyldopa (MD) in their combinations. The first method depends on the first order derivative spectrophotometry by measuring the amplitudes at zero-crossing wavelengths of 286 and 270 nm for HCTZ and MD, respectively. In the second method, partial least squares (PLS) analysis of the ultraviolet absorption spectra of the samples in the 240-340 nm region was applied. The methods were calibrated between 3.5 and 35.7 mg mL-1 for HCTZ and between 2.5 and 25.3 mg mL-1 for MD. For PLS chemometric calibration a concentration set of random mixture consisting of the two drugs in ethanol was prepared. The absorbance data in UV spectra and their dA/dl values were measured for the 24 l points considering Dl= 4 nm. The calibration of the PLS method involves both absorbance-concentration and dA/dl-concentration data matrices. The numerical values were calculated by using Matlab version 6.5 and origin 7.0 software. The results of the methods were statistically compared with each other and a good harmony was found. The developed calibrations were successfully applied for assaying the pharmaceutical formulation of AldorilÒ tablets
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