Browsing by Author "Adegoke, O.A."

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    A new spectrophotometric method for the determination of gabapentin usingchromotropic acid
    (Istanbul Medipol University, 2018) Adegbolagun, O. M.; Thomas, O. E.; Aiyenale, E. O.; Adegoke, O.A.
    The purpose was to develop a colorimetric method for determining gabapentin. The method was based on the diazo coupling reaction between diazotized gabapentin and chromotropic acid. The method was validated using ICH guidelines before its application to generic brands of gabapentin. Coupling reaction generated an orange azo adduct whose absorbance was linearly correlated with concentration in the range of 1-6 μg/mL at 470 nm. The method was accurate and precise with recovery range of 97.6-103.1%; intra- and inter-day precisions (%RSD) were less than 0.65% and showed no statistical difference when compared with reference method in the analysis of the dosage forms. The 3D optimization of the adduct revealed an E-type configuration around the azo linkage which would contribute to its stability. The new method can serve as a reliable alternative to the official method for the routine analysis of gabapentin in bulk and dosage forms.
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    Synthesis, characterization and solvatochromic behaviour of new water-soluble 8-hydroxy-3,6-disulphonaphthyl azohydroxynaphthalenes
    (Taylor & Francis, 2022) Thomas O.E.; Adegoke, O.A.
    A series of five tetracyclic mono azo dyes based on the diazotization of 1-amino-8-hydroxynaphthalene-3,6-disulphonic acid and subsequent coupling with substituted (un)sulphonated naphthalene derivatives have been synthesized. The chemical structures of the dyes were established using UV–visible, IR, NMR as well as mass spectrometry. Based on the number of sulphonic acid and other hydrophilic groups they contain, the compounds showed varying extent of water solubility. Spectroscopic characterization revealed the existence of azohydrazone tautomerism and the influence of the structures of solvating solvents on the equilibrium. Statistical analysis of single, dual and multiparametric equations of Kamlet Abboud and Taft parameters showed that solvent polarity was the most significant contributor to the observed spectral patterns of the dyes in pure solvents. The compounds could find useful applications as solvatochromic probes, food and drug colour additives.