Identification of the Binding Interaction of Anti-tuberculous Drugs with Human Serum Albumin: A Computational Molecular Docking, Fluorescence and Absorption Spectroscopy Study

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Sarfaraaz Vallie
Sivapregasen Naidoo

Abstract

The accuracy in Anti-tuberculous drug assaying was supported by computational modeling using a 2 and 3-dimensional thermodynamic binding affinity prediction of each drug during multiple drug co-administration regimens. The United States Food and Drug Administration has highlighted the need for extensive research to improve the recovery during analytical drug method development, where the recovery affects the slope of the calibration curve. Here we focused on the drug-protein binding variation that affects the extrapolation of the patient sample drug concentration from the slope of the calibration curve. The binding constants calculated at a physiological temperature from the fluorescence spectroscopy data were as follows: Rifampicin 5.379 X 102 M-1 (moderate affinity), Isoniazid 9.285 M-1 (low affinity), 25-Desacetyl Rifampicin 3.156 M-1 (low affinity), Ethambutol 3.443 M-1 (low affinity) and Pyrazinamide 3.076 X 102 M-1 (moderate affinity). These drugs Gibbs free energy were below zero, indicating spontaneous binding reactions. Rifampicin a non-polar weak acid with a higher affinity indicating the most stable complex formation with albumin as opposed to soluble Isoniazid due to it being polar and an ionized form to be easily excreted in the urine resulting in low levels of detection. This will affect the bioavailability and accuracy of the assay levels for patients experiencing hyper and hypoalbuminemia with related competition and induction processes of the enzymes. These complications are apparent where larger numbers of patients are involved in clinical trials, bioequivalence and bioavailability studies with varying protein levels that may be more crucial for drugs with a narrow therapeutic index.

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How to Cite
1.
Vallie S, Naidoo S. Identification of the Binding Interaction of Anti-tuberculous Drugs with Human Serum Albumin: A Computational Molecular Docking, Fluorescence and Absorption Spectroscopy Study. IJPQA [Internet]. 25Mar.2020 [cited 2Jul.2020];11(01):01-4. Available from: https://www.ijpqa.com/index.php/IJPQA/article/view/958
Section
Research Article