Molecular complexes of aspirin with humic acid extracted from shilajit and their characterization

Aspirin possesses antipyretic, anti-inflammatory, analgesic and anti-aggregatory activity. The acetylsalicylic acid molecule has a carboxyl group and an ester group. The ester group can be easily hydrolyzed, which reduces the medicinal value and causes side effects on humans. The aim of the present study was to prepare solid complexes between aspirin and humic by lyophilization and solvent evaporation technique in the molar ratio 1:1 and 1:2. Molecular interaction between aspirin and humic acid were studied by DSC, XRD, FT-IR and scanning electron microscopy. This technique clearly demonstrated the existence of solid inclusion complex formation. The lyophilized complex in the molar ratio 1:2 showed enhanced stability and dissolution rates of aspirin significantly. A highly significant (p < 0.05) anti-inflammatory action of the treatment of optimized freeze dried (1:2) aspirin complex with humic acid was evidenced by inhibition of rat paw edema and anti-ulcerogenic action was measured by lowest score (0.63 ± 0.10) with significant reduction in ulceration as compared to aspirin alone.     

Analysis of the dynamics of fuel spray using asymptotic methods: The method of integral invariant manifolds

The current research deals with the thermal explosion and ignition of a mixture of carbon and air. The size distribution of the carbon particles is taken to be continuous and is characterized by a probability density function. The chemical reaction term is presented in the Arrhenius form with variable pre-exponential factor. Transforming the new model to a dimensionless form enables us to rewrite the model in a singular perturbed system of ordinary differential equations. This form of the model enables us to apply the method of integral manifold (MIM). As a result of this method we can derive an explicit expression for the thermal explosion limit which depends on the initial probability density function. Comparing our numerical results to the analytical results, we observe that the effect of the thermal radiation is significant, especially at high temperatures, and cannot be ignored in the analysis of the phenomena of the explosion and ignition.     

Synthesis and characterisation of CoII,NiII and CuII complexes of a tridentate N5 macrocyclic ligand

Summary A novel tridentate macrocyclic ligand was synthesised by the reaction of 2,6-dipicolinic acid hydrazide and 2,3-butanedione. Complexes with Co^II, Ni^II and Cu^II are five-coordinate trigonal bipyramidal on the basis of analyses, electrical conductance, magnetic, electronic and infrared spectral studies. I.r. studies reveal that the ligand coordinates through the pyridine nitrogen and the amido-nitrogen.     

Small-angle X-ray scattering (SAXS) study on nonionic fluorinated micelles in aqueous system

We have investigated the self-organization structures of perfluoroalkyl sulfonamide ethoxylate, C(8)F(17)SO(2)N(C(3)H(7))(CH(2)CH(2)O)(10)H, a nonionic fluorinated surfactant in aqueous system by small-angle X-ray scattering (SAXS) technique. Structural modulation of the nonionic fluorinated micelle induced by temperature change, surfactant concentration, and the added fluorinated oils have been systematically studied. The SAXS data were analyzed by the indirect Fourier transformation (IFT), and the generalized indirect Fourier transformation (GIFT) depending on the volume fraction of the surfactant. Various plausible classical model calculations have been performed to confirm the consistency of the GIFT analysis of the SAXS data. Upon successive increase in temperature, the cylindrical micelles formed at lower temperatures undergo a continuous one-dimensional growth and ultimately near the cloud point an indication of flat planar like structural pattern is observed. The evolution in structure of particle near the demixing temperature may be due to onset of attractive interactions. The shape and size of the micelle is apparently unaffected by changing the surfactant concentration from 1 to 5 wt% at 25 degrees C. Nevertheless, addition of small amount of perfluoropolyether (PFPE) oil, of structure F(CF(2)CF(2)CF(2)O)(n)CF(2)CF(2)COOH (n approximately 21) modulate the micellar shape and size. Long cylindrical micelles eventually transform into globular like particles. The onset cylinder-to-sphere transition in the structure of micelles in the surfactant/water/oil system is probably due to amphiphilic nature of the oil, which tends to increase the spontaneous curvature. The lipophilic part of the oil tends to reside in the micellar core, whereas, the hydrophilic part goes close to the polar head group of the surfactant so that effective cross-sectional area per surfactant molecules increases and as a result spherical micelles tend to form. Perfluorodecalin (PFD) also decreases size of the micelles but its effect is poor compared to the PFPE oil.