Dihydrobis(4-cyano-3-phenylpyrazol-1-yl)borate: homoleptic mononuclear cobalt(II) and copper(II) complexes with a cyano-substituted scorpionate ligand.
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Journal Article↗
Biomedical subjects
N Goswami
Publications and source records attributed to N Goswami.
Structure, physical, and photophysical properties of platinum(II) complexes containing bidentate aromatic and bis(diphenylphosphino)methane as ligands.
This study focuses on a series of PtII(L-L')(dppm)n+ complexes, where dppm is bis(diphenylphosphino)methane and L-L' are C-C' (n = 0), C-N (n = 1), and N-N' (n = 2) aromatic ligands. Structural characteristics are as follows: for [Pt(phen)(dppm)](PF6)2, a N-N' derivative, monoclinic, C2/c, a = 33.583(6) A, b = 11.399(2) A, c = 22.158(4) A, Z = 8; for [Pt(phq)(dppm)](PF6), a C-N derivative, triclinic, P1, a = 11.415(3) A, b = 13.450(3) A, c = 14.210(4) A, Z = 2; for [Pt(phpy)(dppm)](PF6), a C-N derivative, triclinic, P1, a = 10.030(3) A, b = 13.010(2) A, c = 15.066(4) A, Z = 2; and for [Pt(bph)(dppm)], a C-C' derivative, P2(1)/c, a = 17.116(7) A, b = 21.422(6) A, c = 26.528(6) A, Z = 12, where phen is 1,10-phenanthroline, phq is 2-phenylquinoline, phpy is 2-phenylpyridine, and bph is 2,2'-biphenyl. Structural features indicate that the Pt-C bond distance is shorter than the Pt-N bond distance in symmetrical complexes and that the Pt-P bond distance trans to N is shorter than the Pt-P bond trans to C. This is consistent with the 31P NMR spectra where the chemical shift of the P trans to C is approximately 10 ppm less than found for P trans to N. The energy maxima of the metal-to-ligand charge-transfer band for the complexes containing various L-L' ligands occur in the near-UV region of the spectrum and fall into the energy series bpy > bph > phen > 2-phpy > 2-ptpy > 2-phq > 7,8-bzq, where bpy is 2,2'-bipyridine, 2-phpy is 2-phenylpyridine, 2-ptpy is 2-p-tolylpyridine, and 7,8-bzq is 7,8-benzoquinoline. The emission energy maxima, ascribed to variance in metal-perturbed triplet ligand centered emission, commence near 500 nm and follow the series phen > bpy > 7,8-bzq > 2-phpy > 2-ptpy > bph > 2-phq. In general, emission is observed at 77 K and in solution at low temperatures, but the temperature dependence of the emission lifetimes indicates thermal activation to another state occurs with an energy of approximately 1800 cm-1 for the complexes, with the exception of [Pt(bph)(dppm)], which has an activation energy of approximately 2300 cm-1.
Journal Article↗
Rhodium-105 tetrathioether complexes: radiochemistry and initial biological evaluation.
105Rhodium(III) complexes with three different acyclic tetrathioether ligands containing pendant carboxylic acid groups have been synthesized and characterized. The complexes were evaluated for stability under physiological conditions and the most promising complexes were evaluated in vivo in normal mice. The primary route of clearance for these complexes was the renal/urinary system, consistent with the presence of pendant carboxylate groups. The results indicate that the cis-[Rh(III)Cl2(2,5,8,11-tetrathiadodecane-1,12-dicarboxylic acid)]+ complex shows the most promising in vivo characteristics on which to base a potential therapeutic radiopharmaceutical.
Animals↗
Emergency referrals. Stern approach.
A five-year study of a south London health authority's admissions to hospital shows a marked rise in emergency inpatient referrals--with an adverse effect on planned inpatient activity. Jacqueline Mallender and colleagues summarise their findings.
Emergency Service, Hospital↗
An Rh-105 complex of tetrathiacyclohexadecane diol with potential for formulating bifunctional chelates.
1,5,9,13-Tetrathiacyclohexane-3,11-diol (16S4-diol), a sulfur crown ether analog, was studied as a potential chelating agent to complex no-carrier-added (NCA) grade 105Rh(III) in high yield at low ligand concentrations. trans-[RhCl2(16S4-diol)]chi (chi = Cl, PF6) was prepared using nonradioactive RhCl3.3H2O and characterized by UV-Vis, nuclear magnetic resonance (NMR) and X-ray crystallography. It was shown to have a +1 charge with the Rh(III) metal center coordinated to the four S atoms equatorially and two Cl atoms in trans axial positions. The 105Rh-16S4-diol complex prepared with NCA 105Rh(III)-chloride reagent was found to exhibit identical chromatographic properties as trans-[Rh(III)Cl2(16S4-diol)]+ (including silica and C-18 thin-layer chromatography [TLC] and electrophoresis). The preparation of 105Rh-16S4-diol complex formation optimized for conditions of pH, temperature, time, % ethanol and quantity of 16S4-diol resulted in yields > 90%. Very low quantities of 16S4-diol (3 nmol) complex NCA 105Rh(III) under relatively mild reaction conditions (heating at 64 degrees C for 90 min) in the presence of ethanol (10%), yielded the high specific activity 105Rh-16S4-diol complex as a single cationic species. The 105Rh-16S4-diol complex was shown to be stable for > or = 4 days in physiological buffers at room temperature and in human serum at 37 degrees C.
Chelating Agents↗
Topical use of betamethasone-17-benzoate in common dermatological disorders.
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Administration, Topical↗
Preparation and in vitro dissolution of isoniazid from ethylcellulose microcapsules.
Microcapsules of isoniazid were prepared by phase separation coacervation process induced by non-solvent addition and using ethylcellulose (EC) as coating polymer. When polyisobutylene (PIB)--a protective colloid was present at sufficient concentration, film coated drug particles were formed. At 0-6% PIB concentration, the microcapsules were aggregated. Increase of colloid concentration produced microcapsules of less aggregation and higher drug content because coating became progressively thinner. PIB concentration also controlled the particle size and the release rate of drug from microcapsules. Wall thickness and EC loss were calculated from drug content. Microcapsules coated with EC were prepared with 7-9% PIB. Scanning Electron Microscopy was used to study the nature of aggregation and coating behaviour. The in vitro dissolution study confirmed the first order release pattern and also the Higuchi Matrix model.
Antitubercular Agents↗
Product development studies for stabilization of oral liquid enzyme preparations containing diastase and papain.
A product development study was undertaken with a view to stabilize acid sensitive amylolytic enzyme diastase and alkali sensitive proteolytic enzyme papain. An unique high technology method was adopted for both enzymes with enteric coating and non-enteric film forming materials respectively to achieve site specificity of action, better stability and to protect diastase from the adverse acid pH of the stomach. Feasibility of incorporating various excipients like thickening agents, surfactants, preservatives, etc., to produce stable elegant oral liquid suspension was also studied. Release studies of the enzymes both in simulated gastric and simulated intestinal juices showed steady and consistent release. The proteolytic and amylolytic activities were assessed by standard pharmacopoeial methods. The stability of the product during the studies was satisfactory. Reduction in addition of overages of costly enzymes met the project technically feasible and economically viable.
Amylases↗