Browsing by Author "Thomas, O.E."

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    Molecular docking and ADMET studies of the Interaction of 4-carboxyl-2,6-dinitrophenylazohydroxynaphthalenes with Bovine Serum Albumin
    (Faculty of Pharmaceutical Sciences, University of Jos, Nigeria., 2023) Thomas, O.E.
    Previous spectrophotometric investigations revealed strong binding affinities between four potential monoazo colourants (code-named AZ-01 to 04) and bovine serum albumin (BSA) which could dictate the tissue distribution and toxicity of the additives. The molecular docking interactions of the dyes with BSA were analyzed using AutoDock vina and PatchDock in order to elucidate the functional groups involved in complex stabilization. Docking conformations confirmed the ligands preferentially inserted into the hydrophobic cavities of BSA site I. Structure-BSA binding relationships revealed the binding of AZ-02 was driven by hydrogen bond donation from its free phydroxynaphthalene substituent to Ser-479 while the predominantly hydrazone form of its positional isomer, AZ-01, increased its lipophilicity and tendency for hydrophobic interactions. The relatively higher C/H ratio of AZ-03 and -04, which contain additional C-7 substituents, was responsible for their stronger binding and the extensive involvement of their aromatic rings in ligand-site I complex stabilization via Pi-Pi T-shaped, Pi-alkyl and alkyl-alkyl interactions. Moreso, AZ-01, -03 and -04 exist predominantly as hydrazone tautomers with an overall positive charge which provided complementary modes for interaction with negatively charged aspartic and glutamic acids. The structure-BSA binding relationships of the molecules, which can be employed in synthesis of safer congeners, have been elucidated.
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    New spectrophotometric method for the determination of Gabapentin in bulk and dosage forms using p-dimethylaminobenzaldehyde
    (Taylor & Francis, 2018) Adegoke, O. A.; Adegbolagun, O. M.; Aiyenale, E.; Thomas, O.E.
    A new simple, accurate and economic spectrophotometric method based on azo dye derivatization for the determination of gabapentin (GBP) was developed. Critical factors were optimized. The method was validated and assay of dosage forms was done. Spot tests and TLC confirmed the formation of azo adduct. A 0.3M NaNO2 solution using 2M HCl was used for diazotization. The optimal temperature and time were 30°C and 10 min. Azo adducts were determined at 430 nm. Methanol was found to be the best solvent. Gabapentin coupled at a ratio of 1:1 with DMAB. The assays of GBP were linear over the range 1–6 μg/mL (r = 0.9973) and LOD of 0.8322 μg/mL. The methods were accurate (error < 2%) and precise (RSD < 0.5%). The methods were successfully applied to the assay of GBP in dosage forms and compared favorably with reference method (p > .05). The successful diazotization of gabapentin and the azo adduct formation with DMAB is reported for the first time.