Browsing by Author "Lawal, A."

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    Dispersive liquid-liquid microextraction/HPLC techniques for determination of oxytetracycline and doxycycline residues in beef samples: method developments and statistical analysis
    (Nigerian Society of Physical Sciences, 2023-04-10) Aliu, M. A.; Junaid, A. M.; Ibraheem, A.; Ishaq, A.; Lawal, A.; Ayeni, K. E.; Lawal, A. R.; Abdulrauf, L. B.
    A rapid, cost-effective and environment-friendly sample pre-treatment method involving dispersive liquid-liquid microextraction (DLLME) and high-performance liquid chromatography (HPLC) was developed and applied for the extraction of oxytetracycline and doxycycline residues in beef samples (liver, kidney and muscle). Several influencing factors associated with the extraction and separation of these antibiotics residues, such as sample size, type and volume of disperser and extraction solvents, centrifugation speed and time, were optimized using Plackett-Burman design and central composite design, while insignificant factors were fixed at values determined using univariate analysis. Figures of merit of the analytical methodology including the limit of detection (LOD), the limit of quantification (LOQ), accuracy (in terms of average recoveries), precision and calibration functions were established according to the European Union commission decision 2002/657/EC. Linearity, in the range of 5–500 µg/kg, was obtained with regression coefficients ranging from 0.9983 – 0.9999. Inter-day repeatability, intra-day precision, LODs and LOQs obtained were 3.81 – 14.90%, 3.80 – 8.70%, 4.21 – 4.69 µg/kg and 14.02 – 15.65 µg/kg respectively. Samples with detectable drug residues have oxytetracycline being the most commonly detected. The developed method was successfully established and the concentration levels of drug residues detected were lower than the European Union set maximum residue level (MRL).
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    MIXED LIGANDS COMPLEXES OF METRONIDAZOLE: SYNTHESIS AND ANTIBACTERIAL STUDIES
    (MATERIALS SCIENCE AND TECHNOLOGY SOCIETY OF NIGERIA, 2019-11-22) Lawal, A.; Issa, A; Rajee, A.O; Mamman, A; Saadu, H.O.; Bamigboye, M.O,; Babamale, H.F,; Osunniran, W; Busari, H.K
    The synthesis of some transition metal complexes of metronidazole with oxalic acid have been reported and characterized using conductivity measurement, melting point determination, elemental analysis, infrared and ultraviolet/visible spectroscopic methods. Both ligands were bidentate in their moe of coordination with the metal ions. The antibacterial studies were investigated against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Klebsiella pneumonia. Mn(MET)(OXA)Cl2 has the highest inhibition against Klebsiella pneumonia, while Cu(MET)(OXA)Cl2 has the lowest inhibition against Bacillus subtilis.
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    Preparation, Characterization and Antibacterial Activity of Metal Complexes of Mixed Ligands of Nicotinamide and Metronidazole
    (Nigerian Journal of Biochemistry and Molecular Biology, 2017-03-22) Lawal, A.; Ayanwale, P. A.; Rajee, A. O.; Bamigboye, M. O.; Saad, A. O.,; Lawal, M.,; Babamale, H. F.; Nnabuike, G. G.; Yunus-Issa, M. T.; Amolegbe, S.A
    The Mn2+, Fe2+, Cu2+, Co2+, Zn2+ and Ni2+ complexes of mixed nicotinamide and metronidazole were prepared and characterized using solubility, melting point, conductivity measurement, CHNO (carbon, hydrogen, nitrogen, oxygen) elemental analysis, powder X-ray diffraction and infrared spectroscopy . The results of the physical and spectroscopic data confirm the formation of the complexes. For nicotinamide, coordination of the metal to the ligands occurred through the nitrogen of the pyrimidine group, while for mertonidazole, coordination took place through the nitrogen of the amine group. The antibacterial activity of the complexes was carried out against Staphylococcus aureus, Pseudomonas aureginosa, Klebsiella spp, Escherichia coli and Candida spp. Only Cu(II) mixed complex had high inhibitory activity against all three bacteria species. The results of antifungal activity show that all the complexes have no inhibitory activity against the two fungi species compared with the corresponding ligands.
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    SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL STUDIES OF METAL COMPLEXES OF MIXED LIGANDS : CITRIC ACID AND AMODIAQUINE
    (Bayero Journal of Pure and Applied Sciences, 2017-12-02) Lawal, A.; Olowude, S.; Bamigboye, M.O .; Sa’ad, H.O; Amolegbe, S.A.; Yunus-Issa, M.T; Nnabuike, G.G
    A range of d-block transition metals complexes of mixed amodiaquine and citric acid have been synthesized and characterised using microanalytical technique, elemental analysis, FT-IR spectroscopy and magnetic measurement. The results of the analytical and spectroscopic data revealed that both amodiaquine and citric acid acted as bidentate ligands in their mode of coordination with the metal ions.The citric acid bound through the carbonyl (C=O) and hydroxyl groups to the metal ions while, amodiaquine coordinated through the nitrogen atom of the amine and oxygen donor atom of hydroxyl group; resulted in structures with octahedral geometry. Percentage composition and magnetic Bohr moment data indicated that all metal complexes were paramagnetic. Molar conductance measurement indicates that the complexes are non-electrolytes in nature. The antimicrobial activity of the ligands and their mixed complexes was carried out against g(+)Pseudomonas aeruginosa, g(+)E. coli, g(+)Klebsiella pneumonia, g(+)Staphylococcus aureus and g(+)Candida using Muller Hinton diffusion method . The citric acid and amodiaquine result showed low or moderate value from (0.6-0.8) for all the metal complexes with the exception of the Cu (II) complex having inhibitory zones ranging from 1-0-1.3, 0.7-0.9 at 200 ppm respectively. Moreover, the free ligands were found being less active compared with their mixed complexes