title: Spectrophotometric and chemometric determination of hydrochlorothiazide and spironolactone in binary mixture in the presence of their impurities and degradants.
abstract: Hydrochlorothiazide (HCT) and spironolactone (SPR) are mostly co-formulated in antihypertensive formulations. Several methods have been developed and validated for their determination; these methods include spectrophotometric and chemometric-assisted spectrophotometric methods. The developed spectrophotometric methods were isosbestic point (ISO) and ratio subtraction (RS) methods. The absorbance values at 232.4 (lambda(iso1)) and 257.6 nm (lambda(iso2)) were used for determination of the total mixture concentration, while HCT could be directly determined at 317.2 nm (lambda(max)) and by subtraction SPR concentration could be obtained. Also SPR concentration could be calculated by RS method using the absorbance at 243.8 nm (lambda(max)). A wavelength selection method based on genetic algorithm (GAs) was developed and compared to the conventional partial least squares method (PLS). In this method, several parameters were adjusted and the optimum parameter settings were determined using experimental design. The developed chemometric methods were successfully applied for the determination of the HCT and SPR, as well as for determination of their impurities and degradation products. The proposed methods were successfully applied for determination of HCT and SPR in commercial tablets and they were statistically compared to each other and to the reported method. No significant difference was found, providing their accuracy and precision.
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St, Cairo, Egypt. mahahgazy@yahoo.com
authors.forename: Maha A
authors.initials: MA
authors.lastname: Hegazy
authors.forename: Fadia H
authors.initials: FH
authors.lastname: Metwaly
authors.forename: M
authors.initials: M
authors.lastname: Abdelkawy
authors.forename: Nada S
authors.initials: NS
authors.lastname: Abdelwahab
mesh_terms: D000465:Algorithms; D000959:Antihypertensive Agents / Q000032:analysis; D002626:Chemistry, Pharmaceutical; D004338:Drug Combinations; D006852:Hydrochlorothiazide / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods*; D013148:Spironolactone / Q000032:analysis*; D013607:Tablets
chemical_list: D000959:Antihypertensive Agents; D004338:Drug Combinations; D013607:Tablets; D006852:Hydrochlorothiazide; D013148:Spironolactone