Some transition metal complexes of nicotinamide have been prepared and characterized using melting point, conductivity measurement, infrared, electronic, HNMR and atomic absorption spectroscopic methods. . The antibacterial and antifungal studies of the metal complexes and the ligand have been evaluated against Escherichia coli, Staphylococcus and Bacillus subtilis , Aspergillus flavus, Aspergillus niger and penicillum species. It was found that nicotinamide formed stable metal complexes with these metal ions. The analysis of the spectroscopic data shows that nicotinamide act as monodentate, coordinating through the nitrogen atom of the pyridine ring. All the complexes exhibit 4-coordinate geometry. The results of the antimicrobial studies showed that the metal complexes have higher inhibitory activity than the original nicotinamide against the tested bacteria and fungi species. © JASEM http://dx.doi.org/10.4314/jasem.v18 i2.8Introduction:

Mixed complexes of Ibuprofen-Pyrimethamine were synthesized using Cd(II) Co(II), Zn(II), and Mn(II). The mixed complexes were characterized based on some physicochemical and spectroscopic techniques such as infrared, elemental analysis, conductivity measurements, and magnetic moment. Based on the results obtained, the complexes were formulated as [M(L1)(L2)]Cl2, where M = metal ion, L1 = Pyrimethamine, L2 = Ibuprofen). The complexes were found to be non-electrolytes. The ligands act as bidentate towards the central metal ions with deprotonation occurring at the carboxylic group. The complexes were also analyzed by conductometric titration. Antimicrobial screening against the selected organisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus substilis, Bacillus megaterium and Serratia marcescens for the complexes alongside the free ligands were investigated. The antimalarial study was investigated for the compounds against Plasmodium berghei (NK 65 strain). It was observed that the complexes showed significant potentials against the studied organisms.

Metal coordination of bioorganic compounds from both natural and synthetic products is not only gaining recognition in drug design and medicinal inorganic chemistry research, also they are being considered in the improvement of the bioactivity of drugs. What is done in this paper is a review of recent advances in the study of coordination-driven drug delivery, i.e., metal-based drugs (MBDs). The role of some late first row transition metal ions namely Fe, Cu and Zn in the biological activities of metallodrugs such as antimalarials and antimicrobials are highlighted. It was revealed that the interaction between these bio-essential transition metal ions and the organic drugs could enhance the diagnostic and therapeutic potentials of such formed drugs. This is because such interactions were proved to have improved the stability, bioavailability and cell delivery functions of the metallodrugs. Emphasizing on the challenge of metal ions toxicity, the researchers concluded on the need for the development of MBDs to combat drug resistant parasites without causing injury to normal cells. This would be of significance in addressing the concern World Health Organisation of ameliorating the increasing mortality rate in developing countries.

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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.