title: Simultaneous determination of moexipril hydrochloride and hydrochlorothiazide in tablets by derivative spectrophotometric and high-performance liquid chromatographic methods.
abstract: Two new simple and selective assay methods have been presented for the binary mixtures of moexipril hydrochloride (MOEX) and hydrochlorothiazide (HCTZ) in pharmaceutical formulations. The first method depends on second-derivative ultraviolet spectrophotometry with zero-crossing measurements at 215 and 234 nm for MOEX and HCTZ, respectively. The assay was linear over the concentration ranges 1.0-11.0 microg ml(-1) for MOEX and 0.5-9.0 microg ml(-1) for HCTZ. The determination limits for MOEX and HCTZ were found to be 1.0 and 0.5 microg ml(-1), respectively; while the detection limits were 0.2 microg ml(-1) for MOEX and 0.1 microg ml(-1) for HCTZ. The second method was based on isocratic reversed-phase liquid chromatography by using a mobile phase acetonitrile-20 mM phosphate buffer (pH 4.0) (50:50, v/v). Lisinopril was used as an internal standard (IS) and the substances were detected at 212 nm. The linearity range for both drugs was 0.5-12.0 microg ml(-1). The determination and detection limits were found to be 0.100 and 0.010 microg ml(-1) for MOEX and 0.025 and 0.005 microg ml(-1) for HCTZ, respectively. The proposed methods were successfully applied to the determination of these drugs in synthetic mixtures and commercially available tablets with a high percentage recovery, good accuracy and precision.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Istanbul University, 34116, Beyazit, Istanbul, Turkey. serturk@yahoo.com
authors.forename: Sidika
authors.initials: S
authors.lastname: Ertürk
authors.forename: Sevil Müge
authors.initials: SM
authors.lastname: Cetin
authors.forename: Sedef
authors.initials: S
authors.lastname: Atmaca
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006852:Hydrochlorothiazide / Q000032:analysis* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013607:Tablets; D013678:Technology, Pharmaceutical / Q000379:methods*; D044005:Tetrahydroisoquinolines / Q000032:analysis* / Q000737:chemistry
chemical_list: D013607:Tablets; D044005:Tetrahydroisoquinolines; D006852:Hydrochlorothiazide; C058302:moexipril