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1.
J Organomet Chem ; 914: 121219, 2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-32214459

RESUMEN

Methoxy and tert-butyl substituted carboxamide, carboxylic acid and hydrazone Schiff base groups have been assembled into our newly designed fluorenone based ligands and prepared coordination compounds of some first row transition metals and characterized thoroughly with spectroscopic (1H and 13C NMR, IR, GC-MS, UV-Vis), analytical, TGA and molar conductance measurements. The stoichiometry of all the metal complexes is found to be 1: 2 (M: L2) with the general formula, [M(L)2], where L is a singly deprotonated ligand and the geometry of all the metal complexes is found to be octahedral. Ligands and their metal complexes successfully cleaved the pBR322 plasmid DNA and in case of anticancer activity against MCF-7 (human breast adenocarcinoma) cell line, the synthesized compounds found to exhibit excellent activity with prominent apoptotic effect which is characterized by cell shrinkage, cell breakage and turgidity and results were compared with the standard drug cisplatin. Very significant anticancer activity was observed for compounds L1H, Cu(L1)2, Cu(L2)2, Ni(L1)2 and Ni(L2)2 with IC50 value of <10 µgmL-1. Molecular docking studies were performed to assess the bonding mode of synthesized compounds. In case of antioxidant activity study, the compounds L1H, Ni(L1)2, Ni(L2)2, Cu(L1)2 and Cu(L2)2 exhibited significant scavenging activity with good percentage when compared with remaining tested compounds.

2.
J Photochem Photobiol B ; 157: 1-14, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26874303

RESUMEN

The impregnation of halogen atoms in a molecule is an emerging trend in pharmaceutical chemistry. The presence of halogens (Cl, Br, I and F) increases the lipophilic nature of molecule and improves the penetration of lipid membrane. The presence of electronegative halogen atoms increases the bio- activity of core moiety. In the present study, Co(II), Ni(II) and Cu(II) complexes are synthesised using Schiff bases (HL(I) and HL(II)), derived from 8-formyl-7-hydroxy-4-methylcoumarin/3-chloro-8-formyl-7-hydroxy-4-methylcoumarin with 2,4-difluoroaniline/o-toluidine respectively. The synthesized compounds were characterized by spectral (IR, NMR, UV-visible, Mass, ESI-MS, ESR), thermal, fluorescence and molar conductivity studies. All the synthesized metal complexes are completely soluble in DMF and DMSO. The non-electrolytic nature of the metal complexes was confirmed by molar conductance studies. Elemental analysis study suggest [ML2(H2O)2] stoichiometry, here M=Co(II), Ni(II) and Cu(II), L=deprotonated ligand. The obtained IR data supports the binding of metal ion to Schiff base. Thermal study suggests the presence of coordinated water molecules. Electronic spectral results reveal six coordinated geometry for the synthesized metal complexes. The Schiff bases and their metal complexes were evaluated for antibacterial (Pseudomonas aureginosa and Proteus mirabilis), antifungal (Aspergillus niger and Rhizopus oryzae), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activities.


Asunto(s)
Quelantes/síntesis química , Quelantes/farmacología , Cumarinas/química , Halógenos/química , Nitrógeno/química , Oxígeno/química , Bases de Schiff/química , Elementos de Transición/química , Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Quelantes/química , Espectroscopía de Protones por Resonancia Magnética , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría Infrarroja
3.
J Photochem Photobiol B ; 148: 322-332, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26002539

RESUMEN

The Co(II), Ni(II) and Cu(II) complexes have been synthesized with Schiff base (HL), derived from 8-formyl-7-hydroxy-4-methylcoumarin with benzylamine. The Schiff base and its metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The complexes are completely soluble in DMF and DMSO. The molar conductance values indicate that, all synthesized metal complexes are non-electrolytic in nature. Elemental analysis reveals [ML2(H2O)2] stoichiometry, here MCo(II), Ni(II) and Cu(II), L=deprotonated ligand. The coordination between metal ion and Schiff base was supported by IR data, through deprotonation of phenolic oxygen of coumarin and azomethine nitrogen atoms. Solution electronic spectral results unveiled that all the synthesized complexes posses six coordinated geometry around metal ion. Thermal studies suggest the presence of coordinated water molecules. The Schiff base and its metal complexes have been screened for their antibacterial (Escherichia coli, Pseudomonas aureginosa, Klebsiella pneumoniae and Staphylococcus aureus) and antifungal (Penicillium chrysogenum and Aspergillus niger), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activities.


Asunto(s)
Antihelmínticos/síntesis química , Antiinfecciosos/síntesis química , Complejos de Coordinación/síntesis química , ADN/metabolismo , Bases de Schiff/química , Animales , Antihelmínticos/química , Antihelmínticos/farmacología , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antifúngicos/síntesis química , Antifúngicos/química , Antifúngicos/farmacología , Bovinos , Cobalto/química , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Cobre/química , Cumarinas/química , ADN/química , División del ADN/efectos de los fármacos , Espectroscopía de Resonancia por Spin del Electrón , Hongos/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Magnetismo , Níquel/química , Oligoquetos/efectos de los fármacos , Espectrometría de Fluorescencia
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 137: 641-51, 2015 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-25244297

RESUMEN

The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.


Asunto(s)
Cobalto/química , Cobre/química , Cumarinas/química , División del ADN/efectos de los fármacos , ADN/química , Níquel/química , Bases de Schiff/química , Aminas/química , Antihelmínticos/química , Antiinfecciosos/química , Carbono/química , ADN/efectos de los fármacos , Hidrógeno/química , Ligandos , Pruebas de Sensibilidad Microbiana , Modelos Químicos , Nitrógeno/química , Espectrometría de Fluorescencia , Espectrofotometría , Espectrofotometría Infrarroja , Temperatura
5.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 11): o1177-8, 2014 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-25484816

RESUMEN

In the title mol-ecule, C17H12N4OS, the thia-zole ring forms a dihedral angle of 10.8 (2)° with the phenyl ring and an angle of 3.1 (3)° with the indole ring system [which has a maximum deviation of 0.035 (2) Å]. The dihedral angle between the planes of the phenyl ring and the indole ring system is 11.5 (1)°. An intra-molecular N-H⋯O hydrogen bond is observed. In the crystal, pairs of N-H⋯O hydrogen bonds form inversion dimers with an R (2) 2(8) graph-set motif.

6.
Spectrochim Acta A Mol Biomol Spectrosc ; 79(5): 1128-36, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21665524

RESUMEN

A new series of Co(II), Ni(II) and Cu(II) complexes of the type ML·2H2O of Schiff-bases derived from m-substituted thiosemicarbazides and 8-acetyl-7-hydroxy-4-methylcoumarin have been synthesized and characterized by spectroscopic studies. Schiff-bases exhibit thiol-thione tautomerism wherein sulphur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, FAB-mass, ESR and fluorescence), magnetic and thermal studies. The low molar conductance values in DMF indicate that, the metal complexes are non-electrolytes. The cyclic voltammetric studies suggested that, the Cu(II) and Ni(II) complexes are of single electron transfer quasi-reversible nature. The Schiff-bases and its metal complexes have been evaluated for their in vitro antibacterial (Escherichia coli, Staphilococcus aureus, Bascillus subtilis and Salmonella typhi) and antifungal activities (Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The Schiff-base I and its metal complexes exhibited DNA cleavage activity on isolated DNA of A. niger.


Asunto(s)
Antibacterianos/farmacología , Antifúngicos/farmacología , Cobalto/química , Complejos de Coordinación/química , Cobre/química , Cumarinas/química , ADN de Hongos/metabolismo , Níquel/química , Bases de Schiff/química , División del ADN , Espectroscopía de Resonancia por Spin del Electrón , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Espectrofotometría Infrarroja
7.
Nucleosides Nucleotides Nucleic Acids ; 29(9): 658-75, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20706957

RESUMEN

A novel series of 22-membered macrocyclic complexes of the type [MLCl(2)] (M=Co(2+), Ni(2+) and Cu(2+)) have been synthesized with newly derived biologically active ligands (L(1)-L(IV)). These ligands were synthesized by the condensation of ortho-phthalaldehyde and bis-(4-amino-5-mercapto-1, 2, 4-triazole-3-yl)alkanes. The mode of bonding and overall geometry of the complexes have been inferred through IR, EPR, electronic spectral studies, conductivity, magnetic, thermal, and electrochemical studies. All these complexes have been screened for their antibacterial (Escherichia coli, Staphylococus aureus, Salmonella typhi, Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the minimal inhibitory concentration (MIC) method. The DNA cleavage study was done by agarose gel electrophoresis technique.


Asunto(s)
Antiinfecciosos/síntesis química , Antiinfecciosos/farmacología , Fenómenos Químicos , ADN/metabolismo , Triazoles/síntesis química , Triazoles/farmacología , Aldehídos/química , Antiinfecciosos/química , Bacterias/efectos de los fármacos , Cobalto/química , ADN/química , Electroquímica , Electroforesis en Gel de Agar , Hongos/efectos de los fármacos , Magnetismo , Pruebas de Sensibilidad Microbiana , Bases de Schiff/química , Análisis Espectral , Termogravimetría , Triazoles/química
8.
J Enzyme Inhib Med Chem ; 25(3): 430-9, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20370554

RESUMEN

A series of metal complexes of cobalt(II), nickel(II), and copper(II) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 2-amino-4-phenyl-1,3-thiazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The probable structure of the complexes has been proposed on the basis of analytical and spectroscopic data (IR, UV-Vis, ESR, FAB-mass, and thermoanalytical). Electrochemical study of the complexes is also reported. Elemental analysis of the complexes confined them to stoichiometry of the type ML(2).2H(2)O [M = Co(II), Ni(II), and Cu(II)]. The Schiff base and its metal(II) complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes, and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the MIC method. The brine shrimp bioassay was carried out to study their in vitro cytotoxic properties, and also the Schiff base and its metal(II) complexes have been studied for DNA cleavage.


Asunto(s)
Antibacterianos/química , Antifúngicos/química , Complejos de Coordinación/farmacología , Metales Pesados/química , Animales , Antibacterianos/farmacología , Antifúngicos/farmacología , Bacterias/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Cobalto , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Cobre , División del ADN/efectos de los fármacos , Hongos/efectos de los fármacos , Humanos , Níquel , Bases de Schiff , Análisis Espectral , Pruebas de Toxicidad
9.
Artículo en Inglés | MEDLINE | ID: mdl-19962341

RESUMEN

A series of Co(II), Ni(II) and Cu(II) complexes of the type ML(2) have been synthesized with Schiff bases derived from methylthiosemicarbazone and 5-formyl-6-hydroxy coumarin/8-formyl-7-Hydroxy-4-methylcoumarin. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMF indicate that, the complexes are non-electrolytes in nature. In view of analytical, spectral (IR, UV-vis, ESR, FAB-mass and fluorescence), magnetic and thermal studies, it has been concluded that, all the metal complexes possess octahedral geometry in which ligand is coordinated to metal ion through azomethine nitrogen, thione sulphur and phenolic oxygen atom via deprotonation. The redox behavior of the metal complexes was investigated by using cyclic voltammetry. The Schiff bases and their complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by Minimum Inhibitory Concentration method. The DNA cleavage is studied by agarose gel electrophoresis method.


Asunto(s)
Antiinfecciosos/química , Cobalto/química , Cobre/química , Cumarinas/química , División del ADN , Níquel/química , Bases de Schiff/química , Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Técnicas Electroquímicas , Hongos/efectos de los fármacos , Ligandos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Bases de Schiff/farmacología , Solventes/química , Análisis Espectral/métodos
10.
J Enzyme Inhib Med Chem ; 25(1): 87-96, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20030513

RESUMEN

A series of Co(II), Ni(II), and Cu(II) complexes of the type ML.2H2O have been synthesized with Schiff bases derived from 8-formyl-7-hydroxy-4-methylcoumarin and o-phenylenediamine/ethylenediamine. The structure of the complexes has been proposed in the light of analytical, spectral (IR, UV-Vis, ESR, and FAB-mass), magnetic, thermal, and fluorescence studies. The complexes are soluble in DMF and DMSO. The measured molar conductance values indicate that the complexes are non-electrolytes in nature. In view of IR, UV-Vis, and magnetic studies, it has been concluded that all the complexes possess octahedral geometry, in which ligand is coordinated to metal ion through the azomethine nitrogen and phenolic oxygen via deprotonation. Thermal studies provide useful information about the coordination of water molecules to the metal ion and the stability of the complexes. The redox behavior of the complexes has been investigated by an electrochemical method using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the minimum inhibitory concentration method. DNA binding with Co(II) and Cu(II) complexes has been studied by the agarose gel electrophoresis method.


Asunto(s)
Antiinfecciosos/química , ADN/química , Electroquímica/métodos , Metales/química , Bases de Schiff/química , Espectrofotometría Infrarroja/métodos , Espectrofotometría Ultravioleta/métodos , Antiinfecciosos/farmacología , Espectroscopía de Resonancia por Spin del Electrón , Electroforesis en Gel de Agar , Espectrometría de Masa Bombardeada por Átomos Veloces
11.
Eur J Med Chem ; 44(9): 3552-9, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19419802

RESUMEN

A macrocyclic hydrazone Schiff base was synthesized by reacting 1,4-dicarbonyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol and a series of metal complexes with this new Schiff base were synthesized by reaction with Co(II), Ni(II) and Cu(II) metal salts. The Schiff base and its complexes have been characterized by elemental analyses, IR, (1)H NMR, UV-vis, FAB mass, ESR spectra, fluorescence, thermal, magnetic and molar conductance data. The analytical data reveal that the Co(II), Ni(II) and Cu(II) complexes possess 2:1 metal-ligand ratios. All the complexes are non-electrolytes in DMF and DMSO due to their low molar conductance values. Infrared spectral data suggest that the hydrazone Schiff base behaves as a hexadentate ligand with NON NON donor sequence towards the metal ions. The ESR spectral data shows that the metal-ligand bond has considerable covalent character. The electrochemical behavior of the copper(II) complex was investigated by cyclic voltammetry. The Schiff base and its complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Shigella dysentery, Micrococcus, Bacillus subtilis, Bacillus cereus and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Penicillium and Candida albicans) by MIC method. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Hidrazonas/química , Hidrazonas/farmacología , Animales , Antibacterianos/síntesis química , Antibacterianos/toxicidad , Antifúngicos/síntesis química , Antifúngicos/toxicidad , Artemia/efectos de los fármacos , Bacterias/efectos de los fármacos , Cobalto/química , Cobre/química , Huevos , Hongos/efectos de los fármacos , Hidrazonas/síntesis química , Hidrazonas/toxicidad , Compuestos Macrocíclicos/síntesis química , Compuestos Macrocíclicos/química , Compuestos Macrocíclicos/farmacología , Compuestos Macrocíclicos/toxicidad , Pruebas de Sensibilidad Microbiana , Níquel/química , Bases de Schiff/síntesis química , Bases de Schiff/química , Bases de Schiff/farmacología , Bases de Schiff/toxicidad , Pruebas de Toxicidad
12.
J Enzyme Inhib Med Chem ; 24(3): 730-41, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19469711

RESUMEN

A series of metal complexes of La(III) and Th(IV) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 3-substituted-4-amino-5-hydrazino-1,2,4-triazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The structure of the complexes has been proposed by elemental analyses, spectroscopic data i.e. i.r., (1)H nmr, Uv-Vis, FAB-mass and thermal studies. The elemental analyses of the complexes conform to the stoichiometry of the type [La(L).3H2O].2H2O and [Th(L)(NO3).2H2O].2H2O where (L = L(I)-L(IV)). All the complexes are soluble in DMF and DMSO and are non-electrolytes in DMF and DMSO. All these ligands and their complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus and cladosporium) by the MIC method. The brine shrimp bioassay was also carried out to study their invitro cytotoxic properties.


Asunto(s)
Antiinfecciosos/síntesis química , Antiinfecciosos/farmacología , Lantano/química , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/farmacología , Bases de Schiff/química , Torio/química , Triazoles/química , Animales , Antiinfecciosos/química , Antiinfecciosos/toxicidad , Artemia/efectos de los fármacos , Bacterias/efectos de los fármacos , Cationes , Hongos/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Compuestos Organometálicos/química , Compuestos Organometálicos/toxicidad , Espectrofotometría Infrarroja , Termogravimetría
13.
Eur J Med Chem ; 44(7): 2904-12, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19155104

RESUMEN

A series of La(III), Th(IV) and VO(IV) complexes have been synthesized with Schiff bases derived from 8-formyl-7-hydroxy-4-methylcoumarin and o-phenylenediamine/ethylenediamine. The structure of the complexes has been proposed in the light of analytical, spectral (IR, UV-vis, ESR and FAB-mass), Magnetic and thermal studies. The complexes are soluble in DMF and DMSO. The measured molar conductance values indicate that, the complexes are non-electrolytes in nature. The redox behavior of the complexes was investigated by electrochemical method using cyclic voltammetry. The Schiff bases and their complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and cladosporium) by Minimum Inhibitory Concentration method. The DNA cleavage activity of La(III) and VO(IV) metal complexes is studied by agarose gel electrophoresis method.


Asunto(s)
Cumarinas/química , ADN/metabolismo , Lantano/química , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/farmacología , Torio/química , Vanadio/química , Antiinfecciosos/síntesis química , Antiinfecciosos/química , Antiinfecciosos/metabolismo , Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Electroquímica , Espectroscopía de Resonancia por Spin del Electrón , Transporte de Electrón , Electroforesis , Hongos/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Magnetismo , Espectrometría de Masas , Compuestos Organometálicos/química , Compuestos Organometálicos/metabolismo , Espectrofotometría Infrarroja , Temperatura
14.
J Enzyme Inhib Med Chem ; 24(2): 381-94, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18686135

RESUMEN

A series of metal complexes of cobalt(II), nickel(II) and copper(II) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 3-substituted-4-amino-5-hydrazino-1,2,4-triazole and 8-formyl-7-hydroxy-4-methylcoumarin. The probable structure of the complexes has been proposed on the basis of elemental analyses and spectral (IR, Uv-Vis, magnetic, ESR, FAB-mass and thermal studies) data. Electro chemical study of the complexes is also reported. All these complexes are non-electrolytes in DMF and DMSO. All the ligands and their Co(II), Ni(II) and Cu(II) complexes were screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes and Pseudomonas aeruginosa) and antifungal (Aspergillus niger, Aspergillus flavus and cladosporium) activities by MIC method. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties.


Asunto(s)
Antibacterianos/síntesis química , Antifúngicos/síntesis química , Cobalto/química , Cobre/química , Níquel/química , Triazoles/química , Animales , Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Artemia , Ligandos , Pruebas de Sensibilidad Microbiana , Bases de Schiff/química , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta
15.
Eur J Med Chem ; 43(12): 2639-49, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18395942

RESUMEN

A series of metal complexes of cobalt(II), nickel(II) and copper(II) have been synthesized with newly synthesized biologically active 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-5-mercapto-1,2,4-triazole and 8-formyl-7-hydroxy-4-methylcoumarin, which have been characterized by elemental analyses, spectroscopic measurements (IR, UV-vis, fluorescence, ESR), magnetic measurements and thermal studies. Electrochemical study of the complexes is also reported. All the complexes are soluble to limited extent in common organic solvents but soluble to larger extent in DMF and DMSO and are non-electrolytes in DMF and DMSO. All these Schiff bases and their complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa and Salmonella typhi) and antifungal activities (Aspergillus niger, Aspergillus flavus and Cladosporium) by MIC method. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties.


Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Antifúngicos/síntesis química , Antifúngicos/farmacología , Metales Pesados/química , Triazoles/química , Animales , Antibacterianos/química , Antifúngicos/química , Artemia/efectos de los fármacos , Bioensayo , Cobalto/química , Cobre/química , Relación Dosis-Respuesta a Droga , Electroquímica , Espectroscopía de Resonancia por Spin del Electrón , Hongos/efectos de los fármacos , Bacterias Gramnegativas/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Magnetismo , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Níquel/química , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/química , Compuestos Organometálicos/farmacología , Bases de Schiff/química , Espectrometría de Fluorescencia , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta , Estereoisomerismo , Temperatura
16.
J Microencapsul ; 24(3): 274-88, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17454438

RESUMEN

Hydrogel microspheres of chitosan (CS) and Pluronic F127 (PF-127) were prepared by the emulsion-crosslinking method employing glutaraldehyde (GA) as a crosslinker. 5-Fluorouracil (5-FU), an anticancer drug with good water solubility, was encapsulated into hydrogel microspheres. Various formulations were prepared by varying the ratio of CS and PF-127, % drug loading and amount of GA. Microspheres were characterized by Fourier transform infrared (FTIR) spectroscopy to confirm the absence of chemical interactions between drug, polymer and the crosslinking agent. Scanning electron microscopy (SEM) was performed to study the surface morphology of the microspheres. SEM showed that microspheres have smooth shiny surfaces. Particle size, as measured by laser light scattering technique, gave an average size ranging from 110 to 382 microm. Differential scanning calorimetry (DSC) and X-ray diffraction (X-RD) studies were performed to understand the crystalline nature of the drug after encapsulation into hydrogel microspheres. Encapsulation of the drug up to 86% achieved was measured by UV spectroscopy. Equilibrium swelling experiments were performed in distilled water. Diffusion coefficients (D) of water through microspheres were estimated by an empirical equation. In vitro release studies indicated the dependence of release rate on the extent of crosslinking, drug loading and the amount of PF-127 used to produce the microspheres; slow release was extended up to 24 h. The release data were also fitted to an empirical equation to compute the diffusional exponent (n), which indicated that the release mechanism followed the non-Fickian trend.


Asunto(s)
Quitosano/química , Fluorouracilo/química , Hidrogeles , Microesferas , Poloxámero/química , Fluorouracilo/administración & dosificación , Microscopía Electrónica de Rastreo , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
17.
Drug Dev Ind Pharm ; 33(3): 255-64, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17454058

RESUMEN

The main focus of this study is to develop colon targeted drug delivery systems for metronidazole (MTZ). Tablets were prepared using various polysaccharides or indigenously developed graft copolymer of methacrylic acid with guar gum (GG) as a carrier. Various polysaccharides such as GG, xanthan gum, pectin, carrageenan, beta-cyclodextrin (CD) or methacrylic acid-g-guar (MAA-g-GG) gum have been selected and evaluated. The prepared tablets were tested in vitro for their suitability as colon-specific drug delivery systems. To further improve the colon specificity, some selected tablet formulations were enteric coated with Eudragit-L 100 to give protection in an acidic environment. Drug release studies were performed in simulated gastric fluid (SGF) for 2 hr followed by simulated intestinal fluid (SIF) at pH 7.4. The dissolution data demonstrate that the rate of drug release is dependent upon the nature and concentration of polysaccharide/polymer used in the formulations. Uncoated tablets containing xanthan gum or mixture of xanthan gum with graft copolymer showed 30-40% drug release during the initial 4-5 hr, whereas for tablets containing GG with the graft copolymer, it was 70%. After enteric coating, the release was drastically reduced to 18-24%. The other polysaccharides were unable to protect drug release under similar conditions. Preparations with xanthan gum as a matrix showed the time-dependent release behavior. Further, in vitro release was performed in the dissolution media with rat caecal contents. Results indicated an enhanced release when compared to formulations studied in dissolution media without rat caecal contents, because of microbial degradation or polymer solubilization. The nature of drug transport was found to be non-Fickian in case of uncoated formulations, whereas for the coated formulations, it was found to be super-Case-II. Statistical analyses of release data indicated that MTZ release is significantly affected by the nature of the polysaccharide used and enteric coating of the tablet. Differential scanning calorimetry indicated the presence of crystalline nature of drug in the formulations.


Asunto(s)
Antiprotozoarios/administración & dosificación , Sistemas de Liberación de Medicamentos/métodos , Metronidazol/administración & dosificación , Polisacáridos/química , Amebiasis/tratamiento farmacológico , Animales , Antiprotozoarios/farmacocinética , Antiprotozoarios/uso terapéutico , Colon/metabolismo , Masculino , Metronidazol/farmacocinética , Metronidazol/uso terapéutico , Ratas , Ratas Wistar , Comprimidos Recubiertos
18.
J Control Release ; 119(1): 59-68, 2007 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-17331611

RESUMEN

This study reports on the development of novel biodegradable microspheres prepared by water-in-oil-water (W/O/W) double emulsion technique using the blends of poly(d,l-lactide-co-glycolide) (PLGA) and poly(epsilon-caprolactone) (PCL) in different ratios for the controlled delivery of doxycycline (DXY). Doxycycline encapsulation of up to 24% was achieved within the polymeric microspheres. Blend placebo microspheres, drug-loaded microspheres and pristine DXY were analyzed by Fourier transform infrared spectroscopy (FT-IR), which indicated no interaction between drug and polymers. Differential scanning calorimetry (DSC) on drug-loaded microspheres confirmed the polymorphism of DXY and indicated a molecular level dispersion of DXY in the microspheres. Scanning electron microscopy (SEM) confirmed the spherical nature and smooth surfaces of the microspheres produced. Mean particle size of the microspheres as measured by dynamic laser light scattering method ranged between 90 and 200 mum. In vitro release studies performed in 7.4 pH media indicated the release of DXY from 7 to 11 days, depending upon the blend ratio of the matrix. Up to 11 days, DXY concentrations in the gingival crevicular fluid were higher than the minimum inhibitory concentration of DXY against most of the periodontal pathogens. One of the developed formulations was subjected to in vivo efficacy studies in thirty sites of human periodontal pockets. Significant results were obtained with respect to both microbiological and clinical parameters up to 3 months even as compared to commercial DXY gel. Statistical analyses of the release data and in vivo results were performed using the analysis of variance (ANOVA) method.


Asunto(s)
Doxiciclina/administración & dosificación , Sistemas de Liberación de Medicamentos/métodos , Ácido Láctico/administración & dosificación , Microesferas , Bolsa Periodontal/tratamiento farmacológico , Poliésteres/administración & dosificación , Ácido Poliglicólico/administración & dosificación , Polímeros/administración & dosificación , Doxiciclina/farmacocinética , Evaluación Preclínica de Medicamentos , Humanos , Ácido Láctico/farmacocinética , Bolsa Periodontal/metabolismo , Bolsa Periodontal/patología , Poliésteres/farmacocinética , Ácido Poliglicólico/farmacocinética , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Polímeros/farmacocinética , Distribución Aleatoria
19.
Drug Dev Ind Pharm ; 33(1): 79-90, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17192254

RESUMEN

The present study was performed to evaluate the possibility of using modified xanthan films as a matrix system for transdermal delivery of atenolol (ATL), which is an antihypertensive drug. Acrylamide was grafted onto xanthan gum (XG) by free radical polymerization using ceric ion as an initiator. Fourier transform infrared spectroscopy and differential scanning calorimetry indicated the formation of the graft copolymer. The obtained graft copolymer was loaded with ATL and films were fabricated by solution casting method for transdermal application. Various formulations were prepared by varying the grafting ratio, drug loading, and different penetration enhancers. The formulations prepared were characterized for weight, thickness uniformity, water vapor transmission rate, and uniformity in drug content of the matrix. All the thin films were slightly opaque, smooth, flexible, and permeable to water vapor, indicating their permeability characteristics suitable for transdermal studies. Fourier transform infrared spectroscopy and differential scanning calorimetry studies indicated no significant interactions between drug and polymer. Drug is distributed uniformly in the matrix but showed a slight amorphous nature. Drug-loaded films were analyzed by X-ray diffraction to understand the drug polymorphism inside the films. Scanning electron microscopic studies of the placebo and drug-loaded films demonstrated a remarkable change in their surface morphology. The skin irritation tests were performed in mice and these results suggested that both placebo and drug-loaded films produced negligible erythema and edema compared to formalin (0.8% v/v) as the standard irritant. The in vitro drug release studies were performed in phosphate buffer saline using a Keshary-Chien diffusion cell. Different formulations were prepared and variations in drug release profiles were observed. Release data were analyzed by using the Ritger and Peppas equation to understand the mechanism of drug release as well as the estimation of n values, which ranged between 0.41 and 0.53, suggesting a Fickian diffusion trend.


Asunto(s)
Atenolol/administración & dosificación , Polisacáridos Bacterianos/administración & dosificación , Resinas Acrílicas/administración & dosificación , Administración Cutánea , Animales , Atenolol/química , Preparaciones de Acción Retardada , Ratones , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
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