Use of an oxidation reaction for the quantitative determination of albendazole with Chloramine-T and acid dyes.

One titrimetric and two spectrophotometric procedures have been reported for the determination of albendazole and its tablets. Using titrimetry, the drug was titrated directly with Chloramine-T under acidic conditions using a Methyl Orange indicator. The spectrophotometric procedures involve treating the sample solution with a measured excess of Chloramine-T in an acid medium, followed by an estimation of unreacted Chloramine-T by reacting with a fixed amount of either Methyl Orange or Indigo Carmine dye solution and measuring the absorbance at 510 nm or 610 nm. The stoichiometric ratio, which forms the basis for the calculations in titrimetry as well as the range of the applicability, are reported. The Beer's law range and sensitivity values for spectrophotometric procedures are included. The methods were applied to the determination of albendazole in tablets with satisfactory results.     

Influence of gadolinium on magnetization and DC resistivity of Ni-Zn nanoferrites

The study of gadolinium substitution in small amounts on the saturation magnetization and DC resistivity of nickel-zinc nanoferrite has led to the understanding of the degree of formation of a secondary orthoferrite GdFeO₃ phase, the generation of cationic and oxygen vacancies and the dilution of gadolinium in the lattice. The role of secondary phase in modifying the electromagnetic properties has been stressed by making further investigations on the Curie temperature and the activation energies.     

Neighborhood contraction in graphs

Let G be a graph and v be any vertex of G. Then the neighborhood contracted graphG_v of G, with respect to the vertex v, is the graph with vertex set V ? N(v), where two vertices u,w ∈ V ? N(v) are adjacent in G_v if either w = v and u is adjacent to any vertex of N(v) in G or u,w ? N[v] and u,w are adjacent in G. The properties of the neighborhood contracted graphs are discussed in this paper. The neighborhood contraction in some special class of graphs, the domination in a graph and the neighborhood contracted graphs are discussed in the paper.     

Three useful bromimetric methods for the determination of salbutamol sulfate

Three different methods developed for the determination of salbutamol sulfate (SBS), in pure drug form and in dosage forms, are discussed. The methods are based on the oxidation–bromination reaction of the drug by bromine generated in-situ by the interaction of bromate with bromide in acid medium. In titrimetry the drug is titrated directly with bromate in the presence of a large excess of bromide and in sulfuric acid medium using methyl red as indicator. Spectrophotometry is based on addition of a measured excess of bromate–bromide mixture to the sample solution in sulfuric acid medium followed by the estimation of surplus bromine by reacting it with a definite amount of methyl orange dye and measuring the absorbance at 510 nm. The amount of bromate reacting corresponds to the sample content. The kinetic method depends on the linear relationship between the concentration of the drug and time for oxidation and bromination as indicated by the bleaching of the methyl orange acid colour by the bromine generated in situ. Titrimetry is applicable in the 2–20 mg range. In spectrophotometry, Beer's law is obeyed in the 0.5–5.0 g mL^–1 range whereas concentrations in the 5.0–25.0 g mL^–1 range can be determined by the kinetic method. The effect of common excipients and additives in tablets is discussed. The procedures have been successfully applied to dosage forms; the results agree well with those obtained by use of a reference method. The methods can be used to determine SBS at mg or g levels.     

NMR investigations of self-aggregation characteristics of SDS in a model assembled tri-block copolymer solution

The present work was undertaken with a view to understand the influence of a model non-ionic tri-block copolymer PEO-PPO-PEO (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)) with molecular weight 5800 i.e., P123 [(EO)(20)-(PO)(70)-(EO)(20)] on the self-aggregation characteristics of the anionic surfactant sodium dodecylsulfate (SDS) in aqueous solution (D(2)O) using NMR chemical shift, self-diffusion and nuclear spin-relaxation as suitable experimental probes. In addition, polymer diffusion has been monitored as a function of SDS concentration. The concentration-dependent chemical shift, diffusion data and relaxation data indicated the significant interaction of polymeric micelles with SDS monomers and micelles at lower and intermediate concentrations of SDS, whereas the weak interaction of the polymer with SDS micelles at higher concentrations of SDS. It has been observed that SDS starts aggregating on the polymer at a lower concentration i.e., critical aggregation concentration (cac=1.94 mM) compared to polymer-free situation, and the onset of secondary micelle concentration (C(2)=27.16 mM) points out the saturation of the 0.2 wt% polymer or free SDS monomers/micelles at higher concentrations of SDS. It has also been observed that the parameter cac is almost independent in the polymer concentrations of study. The TMS (tetramethylsilane) has been used as a solubilizate to measure the bound diffusion coefficient of SDS-polymer mixed system. The self-diffusion data were analyzed using two-site exchange model and the obtained information on aggregation dynamics was commensurate with that inferred from chemical shift and relaxation data. The information on slow motions of polymer-SDS system was also extracted using spin-spin and spin-lattice relaxation rate measurements. The relaxation data points out the disintegration of polymer network at higher concentrations of SDS. The present NMR investigations have been well corroborated by surface tension and conductivity measurements.     

Synthesis and evaluation of novel 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole tethered chalcone hybrids as potential anticancer agents

A series of novel 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole tethered chalcone derivatives were designed synthesized by using conventional as well as microwave assisted methods and characterized by ¹H NMR, ¹³C NMR and mass spectral analysis. Microwave assisted synthesis caused an improvement in yield and significant reduction in the reaction time of all the derivatives. All the new synthesized derivatives were further evaluated for their anti-cancer activity against selected four human cancer cell lines; A549 (Lung), MCF-7 (Breast), Colo-205 (Colon) and A2780 (Ovarian). Among the synthesized compounds, 7b , 7c , 7d , 7e , 7g and 7h exhibited potent anticancer activity compared to control drug (etoposide).     

Synthesis of novel piperazine tethered benzocycloheptenone hybrids and their antimicrobial evaluation

A new series of benzosuberone-piperazine hybrids 6a to j were designed and synthesized efficiently in good yields and their structures were confirmed by ¹H NMR, ¹³C NMR, ESI-MS and HRMS. The newly synthesized compounds were evaluated for their in vitro antimicrobial activity against Gram positive, Gram negative bacterial strains and a fungal strain. Among the synthesized compounds, compounds 6c , 6d , 6e , 6f , 6g and 6h exhibited potent antibacterial activity with MIC value of 1.9 μg/mL against Gram positive and Gram negative organisms.     

Chemical composition and antimicrobial activity of essential oil of Heracleum rigens

The essential oil was extracted from the seeds of Heracleum rigens by hydrodistillation and a total of twenty compounds accounting for 98.5% of the total oil composition were identified. Physicochemical properties and chemical composition of the oil was determined by a combination GC/FID and GC/MS analysis. The major compounds identified were bornyl acetate (51.2%), alpha-pinene (22.6%), limonene (9.62%), octyl acetate (3.94%), rho-cymene (2.85%) and gamma-terpinene (1.93%). The antimicrobial activity of the oil was screened by the disc diffusion method against nine pathogenic bacterial strains. Maximum antimicrobial activity was noted against Klebsiella pneumonia and Bacillus subtillis. This investigation corroborates the traditional claim of H. rigens as an effective antimicrobial agent.