Eman I El-Kimary

Alexandria University, Alexandria, Alexandria, Egypt

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Publications (5)10.92 Total impact

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    ABSTRACT: Two stability-indicating chromatographic methods are described for simultaneous determination of amiloride hydrochloride (AMI), atenolol (ATE), and chlorthalidone (CHL) in combined dosage forms. The first method was based on HPTLC separation of the three drugs followed by densitometric measurements of their bands at 274 nm. The separation was carried out on Merck HPTLC silica gel 60F254 aluminum sheets using chloroform-methanol-ammonia 27%, w/w (9 + 2 + 0.3, v/v/v) mobile phase. Analysis data was used for the linear regression graph in the range of 0.1-0.5, 0.8-5.0, and 0.3-1.5 microg/band for AMI, ATE, and CHL, respectively. The second method was based on an RP-HPLC separation of the cited drugs performed on an RP stainless steel C18 analytical column (250 x 4.6 mm id) with a gradient elution system of methanol and 0.05 M aqueous phosphate buffer adjusted to pH 4 as the mobile phase, at the flow rate of 1.0 mL/min. Quantitation was achieved with photodiode array detection at 275 nm for AMI and 225 nm for ATE and CHL. The calibration graphs for each drug were rectilinear in the range of 2-50, 25-150, and 2-100 microg/mL for AMI, ATE, and CHL, respectively. The proposed chromatographic methods were successfully applied for determination of the investigated drugs in pharmaceutical preparations. Both methods were validated in compliance with International Conference on Harmonization guidelines in terms of linearity, accuracy, precision, robustness, LOD, and LOQ.
    Journal of AOAC International 01/2013; 96(2):313-23. · 1.23 Impact Factor
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    ABSTRACT: HPLC-DAD method based on solid-phase extraction was developed for residual determination of metronidazole (MET) and its metabolite hydroxymetronidazole (MET-OH) in two strains of hen eggs (Alexandria egg line, AE and Fayoumi egg line, PP). The LC separation was performed on a RP C-18 analytical column (150 mm × 4.6 mm, 5 µm) with an isocratic elution system of 0.0 5 M phosphate buffer of pH 2.5–acetonitrile (95:5) as the mobile phase. The procedure was evaluated and fully validated. The calibration graphs for MET and MET-OH were rectilinear in the range of 0.3–16.0 µg g−1 for MET and 0.2–20.0 µg g−1 for MET-OH. No residues could be detected before the 3rd day or after 11th day after the drug administration. The drug and metabolite concentration levels in eggs for the two strains of hens were different owing to their change in genetic potential. PP has less ability to keep MET and MET-OH residues than AE.
    Journal of Liquid Chromatography &amp Related Technologies 01/2013; 36(14). · 0.57 Impact Factor
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    ABSTRACT: An efficient chromatographic method for the simultaneous determination of triamterene (TRI) and xipamide (XIP) in urine samples, based on high performance liquid chromatography with photodiode array detector (HPLC-DAD) has been developed. The HPLC separation was performed on a RP stainless-steel C-18 analytical column (250 mm × 4.6 mm, 5 μm) with a gradient elution system of 0.05 M phosphate buffer adjusted to pH 4.0 and methanol as the mobile phase. The method was used to determine the urinary excretion profile and to calculate different urinary pharmacokinetic parameters following oral dose of their combination compared with single oral doses of each drug and hence comparing their bioavailability. Quantitation was performed using chlorthalidone as internal standard. The calibration graphs of each drug were rectilinear in the range of 0.2-40 μg/mL urine for TRI and 0.2-15 μg/mL urine for XIP. An HPLC-DAD method was also successfully developed for the simultaneous determination of the investigated drugs in pharmaceutical preparations. The methods were validated in terms of linearity, accuracy, precision, selectivity, limits of detection and quantitation and other aspects of analytical validation.
    Journal of pharmaceutical and biomedical analysis 12/2011; 61:78-85. · 2.45 Impact Factor
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    ABSTRACT: Two spectrophotometric methods are presented for the simultaneous determination of ezetimibe/simvastatin and ezetimibe/atorvastatin binary mixtures in combined pharmaceutical dosage forms without prior separation. The first is the derivative ratio method where the amplitudes of the first derivative of the ratio spectra ((1) DD) at 299.5 and 242.5 nm were found to be linear with ezetimibe and simvastatin concentrations in the ranges 0.5-20 µgml(-1) and 1-40 µgml(-1) , respectively, whereas the amplitudes of the first derivative of the ratio spectra ((1) DD) at 289.5 and 288 nm were selected to determine ezetimibe and atorvastatin in the concentration ranges 5-50 µgml(-1) and 1-40 µgml(-1) , respectively. The second is the H-point standard additions method; absorbances at the two pairs of wavelengths, 228 and 242 nm or 238 and 248 nm, were monitored while adding standard solutions of ezetimibe or simvastatin, respectively. For the analysis of ezetimibe/atorvastatin mixture, absorbance values at 226 and 248 nm or 212 and 272 nm were monitored while adding standard solutions of ezetimibe or atorvastatin, respectively. Moreover, differential spectrophotometry was applied for the determination of ezetimibe in the two mixtures without any interference from the co-existing drug. This was performed by measurement of the difference absorptivities (ΔA) of ezetimibe in 0.07 M 30% methanolic NaOH relative to that of an equimolar solution in 0.07 M 30% methanolic HCl at 246 nm. The described methods are simple, rapid, precise and accurate for the determination of these combinations in synthetic mixtures and dosage forms.
    Drug Testing and Analysis 02/2011; 3(2):97-105. · 3.17 Impact Factor
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    ABSTRACT: Differential pulse voltammetric method was developed for determination of Silymarin (SMR)/Vitamin E acetate (VEA) mixture in pharmaceuticals. SMR and VE gave well-resolved diffusion-controlled anodic peaks at +756 and +444mV, respectively (versus Ag/AgCl) in Britton-Robinson buffer at pH 2.8. The solution conditions and instrumental parameters were optimized for their quantitative determination. The linear response was obtained in the range 0.1-4.0mgL(-1) with a detection limit of 0.03mgL(-1) for SMR and 0.05-4.0mgL(-1) with a detection limit of 0.01mgL(-1)for VEA.
    Talanta 02/2008; 74(4):773-8. · 3.50 Impact Factor