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17 results on '"Rasheed N"'

14. Unraveling the binding characteristics of the anti-HIV agents abacavir, efavirenz and emtricitabine to bovine serum albumin using spectroscopic and molecular simulation approaches

Author

Amer M. Alanazi, Ali S. Abdelhameed, Ayman Alkhider, Ahmed H. Bakheit, Fahad M. Almutairi, Ibrahim A. Darwish, and Rasheed N. Herqash

Subjects
0301 basic medicine, 030103 biophysics, Efavirenz, biology, Anti hiv, Molecular simulation, Condensed Matter Physics, Emtricitabine, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, 03 medical and health sciences, chemistry.chemical_compound, 030104 developmental biology, chemistry, Abacavir, Materials Chemistry, medicine, biology.protein, Biophysics, Physical and Theoretical Chemistry, Bovine serum albumin, Binding site, Tyrosine, Spectroscopy, medicine.drug
Abstract

In the present study the binding characteristics of abacavir (ABV), efavirenz (EFV) and emtricitabine (EMC) to bovine serum albumin (BSA) have been investigated via the use of spectroscopic tools and in silico docking studies. Those ligands were found to statically quench the intrinsic fluorescence of BSA with binding constants ranging between 1.75 and 2.36 × 104 Lmol− 1 over the studied temperatures. Fluorescence quenching results were further interpreted to obtain the thermodynamic features of the interactions which revealed spontaneous interactions between the studied ligands and BSA with ΔH° values of − 10.50, − 2.56 and − 2.89 kJmol− 1 and ΔS° values of of 47.46, 74.14 and 71.88 Jmol− 1 K− 1 for ABV, EFV and EMC, respectively. Synchronous fluorescence measurments showed that the intrinsic fuorescence of BSA was being quenched by the 3 ligands with a suggested alteration in the microenvironments around the tyrosine residues of the BSA upon binding to ABV and EMC. Furthermore, markers of the BSA binding sites were incorportated to identify the binding site(s) on BSA for ABV, EFV and EMC. It was found that ABV and EMC bind to Sudlow sites I and II on the BSA while EFV binds only to site I which was further supported with the molecular docking findings.

Published
2018
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16. Simultaneous quantitative determination of seven novel tyrosine kinase inhibitors in plasma by a validated UPLC-MS/MS method and its application to human microsomal metabolic stability study

Author

Essam Ezzeldin, Rasheed N. Herqash, Toqa El-Nahhas, and Muzaffar Iqbal

Subjects
Electrospray ionization, Clinical Biochemistry, Ethyl acetate, 030226 pharmacology & pharmacy, 01 natural sciences, Biochemistry, High-performance liquid chromatography, Analytical Chemistry, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Limit of Detection, Tandem Mass Spectrometry, Liquid chromatography–mass spectrometry, Microsomes, Enzyme Stability, medicine, Humans, Sample preparation, Protein Kinase Inhibitors, Chromatography, High Pressure Liquid, Chromatography, medicine.diagnostic_test, Elution, 010401 analytical chemistry, Selected reaction monitoring, Reproducibility of Results, Cell Biology, General Medicine, Protein-Tyrosine Kinases, 0104 chemical sciences, chemistry, Therapeutic drug monitoring, Linear Models
Abstract

A rapid, sensitive and reproducible ultra-high performance liquid chromatography mass spectrometry method was developed and validated for simultaneous determination of seven tyrosine kinase inhibitors (dasatinib, foretinib, osimertinib, gefitinib, ibrutinib, linifanib and motesanib) in human plasma samples using quizartinib as internal standard (IS). The sample preparation was performed by liquid-liquid extraction method, using a mixture of ethyl acetate and tert butyl methyl ether (50:50, v/v) as extracting solvents. Chromatographic separation was achieved using acquity UPLC BEH C18, 1.7 µm 2.1 × 100 mm column and a mobile phase consisting of a mixture of acetonitrile (0.1% formic acid) and 20 mM ammonium acetate (95:5) at a flow rate of 0.25 mL/min. All the analytes and IS were eluted within 2 min, with total run time of 3 min only. The electrospray ionization in positive mode was used and all analytes were monitored using multiple reaction monitoring (MRM) mode. The method was linear and reproducible for all the compounds in the range of 5–1000 ng/mL. Between- and within-run accuracy ranged from 86.7% to 92.5%, and the precision was less than 11.9% for all seven compounds. The developed method was successfully applied to in-vitro human microsomal metabolic stability study. This method could be useful in clinical application for therapeutic drug monitoring (TDM) of these analytes and for individualization of therapeutic regimens.

Published
2020
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