Synthesis and in vitro Bio-activity Evaluation of N4-benzyl Substituted 5-Chloroisatin-3-thiosemicarbazones as Urease and Glycation Inhibitors

A series of fifteen N4-benzyl substituted 5-chloroisatin-3-thiosemicarbazones 5a-o were synthesized and screened mainly for their antiurease and antiglycation effects. Lemna aequinocitalis growth and Artemia salina assays were carried out to determine their phytotoxicity and cytotoxicity potential. All the compounds proved to be extremely effective urease inhibitors, demonstrating enzyme inhibition much better than the reference inhibitor, thiourea (IC50 values 1.31 ± 0.06 to 3.24 ± 0.15 vs. 22.3 ± 1.12 μM). On the other hand, eight out of fifteen compounds tested, i.e. 5b, 5c, 5h-k, 5m and 5n were found to be potent glycation inhibitors. Of these, five viz. 5c, 5h-j and 5n proved to be exceedingly efficient, displaying glycation inhibition greater than the reference inhibitor, rutin (IC50 values 114.51 ± 1.08 to 229.94 ± 3.40 vs. 294.5 ± 1.5 μM).

Synthesis, crystal structure, molecular docking studies and bio-evaluation of some N4-benzyl-substituted isatin- 3-thiosemicarbazones as urease and glycation inhibitors

Fifteen N4-benzyl-substituted isatin-3-thiosemicarbazones 5a–o were synthesized and evaluated for their urease and glycation inhibitory potential. Lemna aequinocitalis growth and Artemia salina assays were also done to determine their phytotoxic and toxic effects. All compounds are potent inhibitors of the urease enzyme, displaying inhibition [half maximal inhibitory concentration (IC50)=1.08±0.12–11.23±0.19 μm] superior to that of the reference inhibitor thiourea (IC50=22.3±1.12 μm). Compounds 5c, 5d, 5h, 5j,k are potent antiglycating agents, showing glycation inhibitory activity better than that of the reference inhibitor rutin (IC50 values 209.87±0.37–231.70±6.71 vs. 294.5±1.5 μm). In the phytotoxicity assay, 11 thiosemicarbazones 5a–d, 5g, 5h, 5j–l, 5n,o are active, demonstrating 5–100% growth inhibition of L. aequinocitalis at the highest tested concentrations (1000 or 500 μg/mL). In the brine shrimp (A. salina) lethality bioassay, three derivatives 5b, 5j and 5o are active with median lethal dose (LD50) values of 3.63×10−5, 2.90×10−5 and 2.31×10−4 m, respectively.

Synthesis, biological evaluation and docking studies of some novel isatin-3-hydrazonothiazolines

The putative binding mode of compound 6i in the active site of Jack bean urease.

Synthesis, cytotoxic and urease inhibitory activities of some novel isatin-derived bis-Schiff bases and their copper(ii) complexes

The putative binding mode of the most active compound 3b in the active site of Jack bean urease.

Improved physicochemical characteristics of artemisinin using succinic acid

Artemisinin (ARMN) is a potent antimalarial drug, which is effective against multidrug resistant strains of Plasmodium falciparum and produces rapid recovery even in patients with cerebral malaria. Being poorly soluble in water, artemisinin is incompletely absorbed after oral intake due to poor dissolution characteristics in the intestinal fluids. To enhance these properties, solid dispersions of artemisinin with succinic acid (SUC) were prepared using drug-carrier ratios 1 : 1, 1 : 4, 1 : 6, 1 : 8 and 1 : 10 by solvent evaporation and freeze drying methods. These solid dispersions were characterized by differential scanning calorimetery (DSC), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction patterns (XRD), phase solubility and dissolution kinetics evaluated by applying zero order, first order, Higuchi, and Korsmeyer-Peppas models. Physical mixtures produced significantly higher aqueous solubility and rate of dissolution as compared to artemisinin alone. The dissolution profiles of all formulations followed Higuchi model and exhibited diffusion-controlled release of drug. Solvent evaporation method (SLVPs) exhibited improved solubility and freeze dried solid dispersions (FDSDs) produced highest solubility but stability constant was opposite. ARMN and SUC both were found completely crystalline as shown by their XRD patterns. Physical mixtures (PMs) showed reduced intensity in their XRD patterns while solid dispersions by SLVPs exhibited twice reduced intensity and much displaced angles, whereas FDSDs showed synergistic effects in some of ARMN and SUC peaks. DSC thermograms of FDSDs at drug-carrier ratios 1 : 1-1 : 4 showed lower melting temperature and enthalpy change (deltaH) values than respective SLVPs, whereas at higher ratios, a reverse was true. SLVPs showed displaced methyl stretching bands at lower drug-carrier ratios and exhibited O-H stretching characteristic bands of SUC at higher drug-carrier ratios. In addition, carbonyl group and C-O stretching vibrations characteristic of SUC (1307 cm(-1)) appeared prominently compared to PMs, whereas C-O stretching characteristic bands of ARMN disappeared at higher ratios. FDSDs exhibited distinct nature of bonding compared to respective SLVPs and PMs.

(2Z)-N-(2-Chlorobenzyl)-2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)hydrazinecarbothioamide

In the title compound, C₁₆H₁₃ClN₄OS, the isatin ring system is oriented at dihedral angles of 10.60 (7) and 72.60 (3)° with respect to the thio­semicarbazide and 2-chloro­benzyl groups, respectively. The near planarity of the isatin and thio­semicarbazide groups [r.m.s. deviations of 0.0420 and 0.0163 Å, respectively] is reinforced by intra­molecular N—H⋯O and N—H⋯N hydrogen bonds, which generate S(6) and S(5) rings, respectively. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R₂²(8) loops. Aromatic π–π stacking inter­actions between the centroids of heterocyclic five-membered and benzene rings [distance = 3.6866 (11) Å] are also observed.

Improved physicochemical characteristics of artemisinin-nicotinamide solid dispersions by solvent evaporation and freeze dried methods

Artemisinin (ARMN) is a drug of choice against drug-resistant malaria especially due to Plasmodium falciparum. Being poorly soluble in water, its solid dispersions with nicotinamide (NA) were prepared at various drug-carrier ratios (1:1, 1:4, 1:6, 1:8, 1:10) by solvent evaporation and freeze drying methods. These solid dispersions were characterized by differential scanning calorimetery (DSC), fourier transform infrared spectroscopy (FTIR), X-ray diffraction patterns (XRD), phase solubility and dissolution studies. Artemisinin and nicotinamide both were found completely crystalline as shown by their XRD patterns. Physical mixtures (PMs) showed decreased intensity in their XRD patterns while solid dispersions by solvent evaporation method (SLVPs) exhibited displaced angles and decreased intensity whereas freeze dried solid dispersions (FDSDs) showed least number of peaks having low intensity and maximum displaced angles. DSC thermograms of drug-carrier ratios at 1:1-1:4 showed lower melting temperature than artemisinin and nicotinamide in all preparations. Endothermic temperature of artemisinin in PMs and SLVPs increased with rise of nicotinamide content upto 1:6 ratio followed by decline. All samples showed crystallization temperature below the artemisinin except drug-carrier ratio 1:6 of PMs while δH value was minimum at this ratio. FDSDs produced lowest endothermic temperature than corresponding PMs and SLVPs. SLVPs exhibited band shifting in both functional and fingerprint region compared to respective PMs as exhibited by their FTIR spectra. FDSDs and SLVPs showed different nature of bonding among artemisinin and nicotinamide. FDSDs produced strongest CONH(2) bonding followed by SLVPs and PMs respectively. PMs produced significantly higher aqueous solubility and rate of dissolution as compared to artemisinin alone. SLVPs exhibited improved solubility and dissolution profile corresponding to PMs. FDSDs showed highest release rate and aqueous solubility followed by SLVPs and PMs at all ratios. PMs and SLVPs showed their highest dissolution profile at 1:6 drug-carrier ratio followed by gradual decrease while FDSDs progressed in dissolution rate with increase of nicotinamide content successively upto maximum at 1:10 ratio.

(Z)-4-(3-Fluorophenyl)-1-(5-nitro-2-oxoindolin-3-ylidene)thiosemicarbazide

In the title compound, C₁₅H₁₀FN₅O₃S, an intra­molecular N—H⋯N hydrogen bond generates an S(5) ring, whereas N—H⋯O and C—H⋯S inter­actions complete S(6) ring motifs. The dihedral angle between the isatin ring system and the fluoro­benzene ring is 5.96 (6)° and the complete mol­ecule is close to planar (r.m.s. deviation for all the non-H atoms = 0.112 Å). In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds to form C(8) chains along the [100] direction and C—H⋯O inter­actions are also observed.

Synthesis and Toxicity Evaluation of Some N4-Aryl Substituted 5-Trifluoromethoxyisatin-3-thiosemicarbazones

A series of twenty one N4-aryl substituted 5-trifluoromethoxyisatin-3-thiosemicarbazones 3a-3u was synthesized by the reaction of trifluoromethoxyisatin 1 with different arylthiosemicarbazides 2 in aqueous ethanol (50%), containing a few drops of acetic acid. Their structures were established on the basis of analytical (CHN) and spectral (IR, 1H-NMR, EIMS) data. All the synthesized compounds were evaluated for their toxicity potential by a brine shrimp lethality bioassay. Ten compounds i.e., 3a, 3e, 3i-3l and 3n-3q proved to be active in this assay, displaying promising toxicity (LD50 = 1.11 × 10-5 M - 1.80 × 10-4 M). Amongst these, 3k, 3n and 3o were found to be the most active ones (LD50 = 1.11 × 10-5 M - 1.43 × 10-5 M). Compound 3k showed the highest activity with a LD50 value of 1.11 × 10-5 M and can, therefore, be used as a lead for further studies. Structure-activity relationship (SAR) studies revealed that the presence of strong inductively electron-attracting trifluoromethoxy substituent at position-5 of the isatin moiety played an important role in inducing or enhancing toxic potentiality of some of the synthesized compounds.

4-(3-Fluoro-phen-yl)-1-(2-oxoindolin-3-yl-idene)thio-semicarbazide

In the title compound, C₁₅H₁₁FN₄OS, there are three independent mol­ecules, each with a disordered 3-fluoro­phenyl group [occupancy ratios = 0.547 (17):0.453 (17), 0.645 (5):0.355 (5) and 0.626 (15):0.374 (15)] and displaying dihedral angles of 4.2 (3), 25.2 (6) and 32.4 (5)° between the 2-oxoindoline and fluoro-substituted phenyl rings. Strong intra­molecular N—H⋯N and N—H⋯O and weak intra­molecular C—H⋯S hydrogen bonds complete S(5) and S(6) ring motifs, while strong inter­molecular N—H⋯O hydrogen bonds inter­connect the three independent mol­ecules through R₃³(12) ring motifs. The three-mol­ecule units are in turn linked into polymeric sheets via C—H⋯F and C—H⋯S hydrogen bonds and π–π inter­actions [centroid–centroid distances in the range 3.520 (2)–3.820 (9) Å].

1-(2-Oxoindolin-3-yl-idene)-4-[2-(tri-fluoro-meth-yl)phen-yl]thio-semicarbazide

In the title compound, C₁₆H₁₁F₃N₄OS, the dihedral angle between the aromatic ring systems is 69.15 (10)°. Intra­molecular N—H⋯N and N—H⋯O hydrogen bonds generate S(5) and S(6) rings, respectively. A short N—H⋯F contact also occurs. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R₂²(8) loops. The dimers are linked by N—H⋯F hydrogen bonds, forming polymeric chains propagating in [100]. π–π inter­actions also exist between the centroids of the benzene rings of the 2-oxoindoline group at a distance of 3.543 (3) Å and a short C=O⋯π contact occurs. Two F atoms of the trifluoro­methyl group are disordered over two sets of sites in a 0.517 (8):0.483 (8) ratio.

N-{2-[N-(4-Methyl-phen-yl)oxamo-yl]phen-yl}propanamide

The title compound, C(18)H(18)N(2)O(3), is the product of the heterocyclic ring cleavage at position 2 of 1-propionylisatin. Two centrosymmetric cyclic motifs, viz. R(2) (2)(14) and R(2) (2)(18), are formed by N-H⋯O hydrogen bonds with the propanamide and amino-phenyl units, respectively, as the N-H donors. These motifs combine into two C(2) (2)(8) chain motifs parallel to the b axis. The chain structure is stabilized by C-H⋯π inter-actions between the benzene rings, where C-H is from the phenyl ring of the cleaved part of 1-pro-pionylisatin.

1-[2-Oxo-5-(trifluoro-meth-oxy)indolin-3-yl-idene]-4-[4-(trifluoro-methyl)-phen-yl]thio-semicarbazide

In the title compound, C₁₇H₁₀F₆N₄O₂S, an intra­molecular N—H⋯N hydrogen bonds forms an S(5) ring whereas N—H⋯O and C—H⋯S inter­actions complete S(6) ring motifs. The dihedral angle between the fused ring system and the phenyl ring is 6.68 (8)°. In the crystal, the mol­ecules are dimerized due to N—H⋯O inter­actions. π–π inter­actions are present between the benzene rings [centroid–centroid distance = 3.6913 (15) Å] and between the five membered ring and the trifluoro­meth­yl)phenyl ring [centroids–centroid distance = 3.7827 (16) Å]. One of the trifluoro­meth­oxy F atoms is disordered over two sites with occupancy ratio of 0.76 (3):0.24 (3). The F atoms of the p-trifluoro­methyl substituent are disordered over three sets of sites with an occupancy ratio of 0.70 (2):0.152 (11):0.147 (13).

1-[1-(4-Bromo-phen-yl)ethyl-idene]-4-(2,4-dimeth-oxy-phen-yl)thio-semicarbazide

In the title compound, C(17)H(18)BrN(3)O(2)S, the dihedral angle between the aromatic rings is 9.15 (17)°. A bifurcated intra-molecular N-H⋯(N,O) hydrogen bond generates two S(5) rings and a weak intra-molecular C-H⋯S inter-action completes an S(6) ring motif. In the crystal, inversion dimers linked by pairs of N-H⋯S hydrogen bonds generate R(2) (2)(8) loops and weak C-H⋯S and C-H⋯π inter-actions are also present.

4-(3-Iodo-phen-yl)-1-(2-oxoindolin-3-yl-idene)thio-semicarbazide

In the title compound, C₁₅H₁₁IN₄OS, intra­molecular N—H⋯N, N—H⋯O and C—H⋯S inter­actions generate one S(5) and two S(6) ring motifs. In the crystal, mol­ecules form centrosymmetric dimers via pairs of N—H⋯O inter­actions, generating R₂²(8) ring motifs. In addition a short inter­molecular I⋯S contact of 3.352 (3) Å is observed.

1-Acetyl-3-[2-(2,3,5,6-tetra-fluoro-phen-yl)hydrazin-1-yl-idene]indolin-2-one

In the title compound, C₁₆H₉F₄N₃O₂, the dihedral angle between the aromatic ring systems is 4.10 (14)° and a bifurcated intra­molecular N—H⋯(O,F) hydrogen bond generates an S(6) ring for the O-atom acceptor and an S(5) ring for the F-atom acceptor. A short C—H⋯O conact also occurs. In the crystal, mol­ecules are linked by C—H⋯O inter­actions.

4-(3-Nitrophenyl)-1-(2-oxoindolin-3-ylidene)thiosemicarbazide

In the title compound, C₁₅H₁₁N₅O₃S, intra­molecular N—H⋯N hydrogen bonding forms an S(5) ring motif, whereas N—H⋯O and C—H⋯S inter­actions type complete S(6) ring motifs. The 2-oxoindoline and 3-methoxy­phenyl rings are almost planar, with r.m.s. deviations of 0.0178 and 0.0149 Å, respectively, and form a dihedral angle of 33.59 (3)°. In the crystal, mol­ecules are inter­linked through the nitro groups in an end-to-end fashion via N—H⋯O and C—H⋯O inter­actions.

4-(3-Methoxyphenyl)-1-(2-oxoindolin-3-ylidene)thiosemicarbazide

In the title compound, C₁₆H₁₄N₄O₂S, intra­molecular N—H⋯N hydrogen bonding forms an S(5) ring, whereas N—H⋯O and C—H⋯S inter­actions complete S(6) ring motifs. In the crystal, mol­ecules form inversion dimers due to N—H⋯O inter­actions. The dimers are inter­linked through N—H⋯S hydrogen bonds and π–π inter­actions occur with a centroid–centroid distance of 3.8422 (11) Å between the meth­oxy-containing benzene ring and the five-membered heterocyclic ring.

4-(2-Ethyl-phen-yl)-1-(2-oxoindolin-3-yl-idene)thio-semicarbazide

The title compound, C₁₇H₁₆N₄OS, is stabilized in the form of a two-dimensional polymeric network due to inter­molecular N—H⋯S and N—H⋯O hydrogen bonds. An intra­molecular N—H⋯N hydrogen bond forms an S(5) ring, whereas inter­actions of the N—H⋯O and C—H⋯S types complete S(6) ring motifs. π–π inter­actions with a centroid–centroid distance of 3.6514 (10) Å are found between the ethyl-substituted benzene ring and the heterocyclic ring of the isatin derivative.

4-(5-Chloro-2-methyl-phen-yl)-1-[2-oxo-5-(trifluoro-meth-oxy)indolin-3-yl-idene]thio-semicarbazide

The asymmetric unit of the title compound, C₁₇H₁₂ClF₃N₄O₂S, contains two mol­ecules, which differ in their planarity and hydrogen bonding. In one mol­ecule, the 2-oxoindolin (C₈/N/O A), thio­semicarbazide (N₃/C/S B) and 5-chloro-2-methyl­phenyl (C₇/Cl C) units are planar with r.m.s. deviations of 0.0110, 0.0173 and 0.0259 Å, respectively. The dihedral angles A/B, B/C and A/C are 1.74 (15), 40.70 (13) and 41.00 (11)°, respectively. In the other mol­ecule the deviations are 0.0455, 0.0007 and 0.0143 Å, respectively, and the dihedral angles are 5.01 (14), 4.53 (16) and 3.38 (13)°, respectively. In both mol­ecules, intra­molecular N—H⋯N and N—H⋯O hydrogen bonds form S(5) and S(6) ring motifs, respectively and C—H⋯S interactions occur. In one of the molecules, an intramolecular C—H⋯F interaction is also present. In the crystal, the mol­ecules are linked by N—H⋯O, C—H⋯F, C—H⋯O and N—H⋯S hydrogen bonding, forming a polymeric network.

4-(2-Fluoro-phen-yl)-1-(2-oxoindolin-3-yl-idene)thio-semicarbazide

The title compound, C(15)H(11)FN(4)OS, is almost planar, the dihedral angle between the aromatic ring systems being 5.00 (13)°. The conformation is stabilized by intra-molecular N-H⋯N and N-H⋯O hydrogen bonds, which generate S(5) and S(6) rings, respectively. N-H⋯F and C-H⋯S inter-actions also occur. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds occur, generating R(2) (2)(8) loops.

1-(5-Nitro-2-oxoindolin-3-yl-idene)-4-o-tolyl-thio-semicarbazide methanol monosolvate

In the title compound, C₁₆H₁₃N₅O₃S·CH₄O, the dihedral angle between the isatin unit and the 2-methyl­phenyl group is 41.81 (2)° and intra­molecular N—H⋯O and N—H⋯N hydrogen bonds occur, generating S(6) and S(5) rings, respectively. In the crystal, polymeric chains arise as a result of N—H⋯O, O—H⋯S and C—H⋯O inter­actions.

(Z)-4-Hexyl-1-(5-nitro-2-oxo-2,3-dihydro-1H-indol-3-yl-idene)thio-semicarbazide

In the title compound, C(15)H(19)N(5)O(3)S, intra-molecular N-H⋯O, N-H⋯N and C-H⋯S inter-actions occur and the three terminal C atoms of the hexyl group are disordered over two sites with an occupancy ratio of 0.664 (12):0.336 (12). In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds occur and C-H⋯O bonds link the dimers into chains. A short C=O⋯π contact is also present.

Antibacterial cobalt (II), copper (II), nickel (II) and zinc (II) complexes of mercaptothiadiazole—derived furanyl, thienyl, pyrrolyl, salicylyl and pyridinyl Schiff bases

A series of Co (II), Cu (II), Ni (II) and Zn (II) complexes of mercaptothiadiazole-derived furanyl, thienyl, pyrrorlyl, salicylyl and pyridinyl Schiff bases were synthesized, characterized and screened for their in vitro antibacterial activity against four Gram-negative, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Shigella fexneri, and two Gram-positive; Bacillus subtilis and Staphylococcus aureous bacterial strains. The results of these studies show the metal complexes to be more antibacterial as compared to the prepared un-complexed Schiff bases.

Isatin-derived Antibacterial and Antifungal Compounds and their Transition Metal Complexes

A series of isatins incorporating thiazole, thiadiazole, benzothiazole and p-toluene sulfonyl hydrazide moieties, along with their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by elemental analyses, molar conductances, magnetic moments, IR, NMR and electronic spectral data. These compounds have been screened for antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi, and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata using the agar-well diffusion method. All the synthesized compounds have shown good affinity as antibacterial and/or antifungal agents which increased in most of the cases on complexation with the metal ions.

Antifungal Cobalt(II), Copper(II), Nickel(II) and Zinc(II) Complexes of Furanyl-,Thiophenyl-, Pyrrolyl-, Salicylyl- and Pyridyl-derived Cephalexins

Some novel cephalexin-derived furanyl, thiophenyl, pyrrolyl, salicylyl and pyridyl Schiff's bases and their cobalt (II), copper (II), nickel (II) and zinc (II) complexes have been synthesized and studied for their antifungal properties against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The presence of metal ions in the investigated Schiff's base complexes reported here lead to significant antifungal activity, whereas the parent ligands were generally less active.

Antibacterial and Antifugal Mono- and Di-substituted Symmetrical and Unsymmetrical Triazine-derived Schiff-bases and their Transition Metal Complexes

A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements. IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies show the metal complexes to be more antibacterial/ antifungal against two or more species as compared to the uncomplexed Schiff-base ligands.

Binding of Transition Metal Ions [Cobalt, Copper, Nickel and Zinc] with Furanyl-, Thiophenyl-, Pyrrolyl-, Salicylyl-and Pyridyl-Derived Cephalexins as Potent Antibacterial Agents

A method is described for the preparation of novel cephalexin-derived furanyl-, thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-containing compounds showing potent antibacterial activity. The binding of these newly synthesized antibacterial agents with metal ions such as cobalt(II), copper(II), nickel(II) and zinc(II) has been studied and their inhibitory properties against various bacterial species such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae are also reported. These results suggest that metal ions to possess an important role in the designing of metal-based antibacterials and that such complexes are more effective against infectious diseases compared to the uncomplexed drugs.

Pharmacokinetic study of copper (II) acetylsalicylate

This study was aimed at determination of pharmacokinetic parameters of copper (II) acetylsalicylate (CAS). Ten volunteers received a 60-mg dose of CAS. Blood samples were collected just before and after 0.25, 0.5, 0.75, 1.0, 1.5, 2.5, 3.0, 3.5, 4.0, 4.5, 5.5, 7.0, 10, and 12.0 h of administration of the drug. The plasma samples were analyzed for CAS and its metabolites by a validated high-performance liquid chromatography method having a suitable lower limit of quantification. The dose of 60 mg was well tolerated without any adverse effect. The maximum plasma concentration of CAS was found to be 0.38 mg L(-1) with t (max) of 0.72 h. The plasma half-life, clearance, and volume of distribution of CAS were 8.67 h, 66.30 L h(-1) and 829 L kg(-1), respectively. The elimination of CAS, acetylsalicylic acid, copper salicylate, and salicylic acid follows the first order kinetics with r (2) 0.979, 0.880, 0.991, and 0.998, respectively. The study provided for the first time the pharmacokinetic data for CAS after oral administration of CAS. The data were found to be useful in understanding the claimed enhanced anti-inflammatory activity of the drug as compared with that of acetylsalicylic acid.

Organometallic-based antibacterial and antifungal compounds: transition metal complexes of 1,1'-diacetylferrocene-derived thiocarbohydrazone, carbohydrazone, thiosemicarbazone and semicarbazone

Organometallic-based, 1,1'-diacetylferrocene-derived antibacterial and antifungal thiocarbohydrazone, carbohydrazone, thiosemicarbazone and semicarbazone have been prepared by condensing equimolar amount of 1,1'-diacetylferrocene with thiocarbohydrazide, carbohydrazide thiosemicarbazide and semicarbazide, respectively. These were used as ligands for the preparation of their cobalt (II), copper (II), nickel (II) and zinc (II) metal complexes. All the synthesized ligands and their complexes were characterized by IR, NMR, elemental analyses, molar conductances, magnetic moments and electronic spectral data. These synthesized compounds were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi, and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata using the agar-well diffusion method. All the compounds showed good antibacterial and antifungal activity which increased on coordination with the metal ions thus, introducing a novel class of organometallic-based antibacterial and antifungal agents.

Antibacterial Co(II), Cu(II), Ni(II) and Zn(II) complexes of thiadiazole derived furanyl, thiophenyl and pyrrolyl Schiff bases

2-Amino-1,3,4-thiadiazole undergoes a condensation reaction with furane-, thiophene- and pyrrole-2-carboxaldehyde to form tridentate NNO, NNS and NNN donor Schiff bases. These Schiff bases were further used to obtain complexes of the type [M(L)2]X, where M = Co(II), Cu(II), Ni(II) or Zn(II), L = L1, L2 or L3 and X = Cl2. The new compounds described here have been characterized by their physical, spectral and analytical data, and have been screened for antibacterial activity against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of the Schiff bases increased upon chelation/complexation in comparison to the uncomplexed Schiff bases against the tested bacterial species thus, opening new approaches to find new ways in the fight against antibiotic-resistant strains.

Surgical approaches for inserting hemiarthroplasty of the hip

BACKGROUND

The operation of insertion of a hemiarthroplasty to the hip refers to replacement of the femoral head with a prosthesis, whilst retaining the natural acetabulum and acetabular cartilage. The main surgical approaches to the hip for insertion of the prosthesis can be broadly categorised as either 'anterior' via the anterior joint capsule, or 'posterior' through the posterior joint capsule.

OBJECTIVES

To evaluate, based on evidence from randomised controlled trials, the effects of different surgical approaches for the insertion of a hemiarthroplasty to the hip has on clinical outcomes.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Injuries Group specialised register (up to February 2002). Articles of all languages were considered.

SELECTION CRITERIA

All randomised controlled trials comparing insertion of a hemiarthroplasty by different surgical approaches.

DATA COLLECTION AND ANALYSIS

Both reviewers independently assessed trial quality, using a 10 item scale, and extracted data. Wherever appropriate and possible, the data are presented graphically.

MAIN RESULTS

One randomised trial was identified involving 114 patients. The trial had poor methodology (particularly in susceptibility to selection bias), inadequate follow-up of patients who withdrew, and there was limited reporting of results. Medical complications and mortality from six months to two years appeared greater in the posterior group; this difference in mortality, within the structure of the poor methodology, was statistically significant. No other differences were claimed to be significant.

REVIEWER'S CONCLUSIONS

There is currently insufficient evidence from randomised trials to determine the optimum surgical approach for insertion of a hemiarthroplasty to the hip.

Results of the long Gamma nail for complex proximal femoral fractures

The results for a series of 35 patients with complex proximal femoral fractures treated with the long Gamma nail are presented. Fracture healing occurred in all surviving patients, but there were four technical problems associated with the implant. Two nails broke associated with delayed union of the fracture necessitating revision of the implant, one fracture of femur at the site of distal locking occurred during surgery and there was one later fracture at the tip of the nail. All but one failures of fixation were revised with another Gamma nail and healed uneventfully. Overall the number of fracture healing complications compares favourably to contemporary implants and improvements in the design and strength of the nail may further improve results.

Staphylococcus epidermidis with intermediate resistance to vancomycin: elusive phenotype or laboratory artifact?

The recent and troubling isolation of Staphylococcus aureus and coagulase-negative staphylococci that have increased resistance to glycopeptide antibiotics has prompted the use of aggressive surveillance measures in the clinical microbiology laboratory to aid in the recognition of these strains. Despite increasing awareness, the confirmation of glycopeptide resistance among staphylococci can be problematic; we present a case of catheter-associated peritonitis caused by Staphylococcus epidermidis to illustrate the dilemma.