title: Spectrophotometric methods for simultaneous determination of ternary mixture of amlodipine besylate, olmesartan medoxomil and hydrochlorothiazide.
abstract: Four, accurate, precise, and sensitive spectrophotometric methods are developed for the simultaneous determination of a ternary mixture containing amlodipine besylate (AM), olmesartan medoxomil (OL) and hydrochlorothiazide (HZ), where AM is determined at its λ(max) 364.6 nm ((0)D), while (OL) and (HZ) are determined by different methods. Method (A) depends on determining OL and HZ by measuring the second derivative of the ratio spectra ((2)DD) at 254.4 and 338.6 nm, respectively. Method (B) is first derivative of the double divisor ratio spectra (D-(1)DD) at 260.4 and 273.0 nm for OL and HZ, respectively. Method (C) based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method then measuring OL and HZ at their isoabsorptive point at 260.0 nm, while HZ is measured using the amplitude of first derivative at 335.2 nm. Method (D) is mean centering of the ratio spectra (MCR) at 252.0 nm and 220.0 nm for OL and HZ, respectively. The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs and their combined dosage form. The obtained results are statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p=0.05.
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Aini Post, 11562 Cairo, Egypt.
authors.forename: Hanan A
authors.initials: HA
authors.lastname: Merey
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Aini Post, 11562 Cairo, Egypt.
authors.forename: Nesrin K
authors.initials: NK
authors.lastname: Ramadan
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Aini Post, 11562 Cairo, Egypt. Electronic address: sherinediab@yahoo.com.
authors.forename: Sherine S
authors.initials: SS
authors.lastname: Diab
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El Aini Post, 11562 Cairo, Egypt.
authors.forename: Azza A
authors.initials: AA
authors.lastname: Moustafa
mesh_terms: D000042:Absorption; D017311:Amlodipine / Q000032:analysis* / Q000737:chemistry; D006852:Hydrochlorothiazide / Q000032:analysis* / Q000737:chemistry; D007093:Imidazoles / Q000032:analysis* / Q000737:chemistry; D000068557:Olmesartan Medoxomil; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000379:methods*; D013777:Tetrazoles / Q000032:analysis* / Q000737:chemistry; D014867:Water
chemical_list: D007093:Imidazoles; D013777:Tetrazoles; D014867:Water; D006852:Hydrochlorothiazide; D017311:Amlodipine; D000068557:Olmesartan Medoxomil
keywords: Double divisor; First derivative ratio spectra; Isoabsorptive point; Mean centering; Successive spectrophotometry; Ternary mixture