Browsing by Author "Elshahed, Mona S"

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    The concept of Relative Absorptivity Distribution for enhancing disbanding power of spectrophotometric technique to resolve co-formulated tablets: A tool for purity index and uniformity assessment
    (Elsevier B.V., 10/05/2020) M.Lotfy, Hayam; Elshahed, Mona S; Mohamed, Dalia
    Resolving the spectral bands of the drugs into their discrete constituents is critical for an effective mathematical spectrophotometric method. The spectral resolution is ordinarily affected by the required application. In the current work an innovative, simple and green Relative Absorptivity Distribution (RAD) concept was established for the successful assay and assessing of content uniformity and purity index of tablet co-formulation which is recommended for lowering the blood glucose level and is comprised of Cangliflozin (CGF) and Metformin CGF and MTF. From the spectrophotometric perspective, the investigation of this combination is challenging as the composition of the tablets is CGF:MTF (1:17), where CGF is not only the minor analyte but also the one of lower absorptivity. The RAD concept is based on the production of master Resolving Spectra (RS). Within the RAD concept and according to the manipulation used for the generation of the RS, three different univariate mathematic methods via spectrophotometer software were developed. The proposed methods are characterized by the ability of extracting the raw spectra of each investigated analyte separately, consequently, enabling each analyte to be determined at its λmax without the contribution of the other. The proposed methods had analyzed CGF in the range 1.0–30.0 μg/mL and MTF within the range 1.0–20.0 μg/mL. The guidelines of the ICH were performed for the complete validation of all methods and the results confirmed satisfactory accuracy, precision and selectivity. The accomplished results together with the simplicity and low-cost of all methods suggested their suitability for the routine quality control analysis of bulk materials, assay of the pharmaceutical formulations and evaluating the content uniformity. Statistical comparison of the results with those of reported HPLC method showed good agreement. In addition, the environmental impact of the proposed methods was assessed by utilizing the National Environmental Methods Index (NEMI), the Analytical Eco-Scale and the Green Analytical Procedure Index (GAPI) where the three tools confirmed the environmentally friendly nature of all proposed methods.
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    Novel LC-MS/MS method for analysis of metformin and canagliflozin in human plasma: application to a pharmacokinetic study
    (BMC, 2019-07) Mohamed, Dalia; Elshahed, Mona S; Nasr, Tamer; Zakaria, Ola
    Highly sensitive and selective liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous estimation of the recently approved oral hypoglycemic mixture; metformin (MET) and canagliflozin (CFZ) in human plasma using propranolol HCl (PPL) and tadalafil (TDF) as internal standards (IS), respectively. Analytes were extracted using protein precipitation induced by acetonitrile then liquid-liquid extraction was performed using ethyl acetate. Reversed phase HPLC was carried out using C18 analytical column (50 mm x 4.6 mm i.d., 5 mu m) with a simple isocratic mobile phase composed of 0.1% formic acid and acetonitrile (60:40, v/v). Detection was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM), with the transitions of m/z 130.2 -> 60.1, m/z 462.3 -> 191.0, m/z 260.2 -> 183.0 and m/z 390.2 -> 268.2 for MET, CFZ, PPL and TDF, respectively, in the positive ion mode. The analysis was carried out within 5 min over a linear concentration range of 50-5000 ng/mL for MET and 10-1000 ng/mL for CFZ. The method was validated in accordance with the FDA guidelines for bioanalytical method. All obtained recoveries were higher than 90.0% while the accuracy was in the range of 88.14-113.05% and the relative standard deviation was below 10.0% for all investigated drugs by the proposed method. The achieved promising results has allowed for the successful application of the developed LC-MS/MS method to a pharmacokinetic study of the target drugs after their oral administration to Egyptian healthy volunteers. The pharmacokinetic study was accomplished after the agreement of the ethics committee.