ONE STEP QUANTIFICATION ANALYTICAL METHOD AND CHARACTERIZATION OF VALSARTAN BY LC-MS

Objective: To develop precise LC-MS method for the estimation of valsartan impurities and perform validation as per ICH guidelines.Methods: Valsartan (VLN) and its degradation products were analyzed by reverse phase high-performance liquid chromatography (RP-HPLC) using mobile phase water: acetonitrile: glacial acetic acid: phosphate buffer in the ratio of 500:500:1:0.5 v/v/v/v at 225 nm using column nucleosil C18, 125 ×4.0 mm, 5 µm. VLN sample (VLN SPL) thus obtained an unknown major impurity (UIMP) of 0.5 % at 0.38 retention time ratio (RRt) and purity of VLN was found to be 98.70 % respectively.Results: Estimation of VLN SPL total unknown impurities was found to be 1.3% by RP-HPLC. In similarly by liquid chromatography mass spectroscopy (LC-MS) a typical chromatogram of valsartan (VLN) at Rt 9.03 min and UIMP at Rt 3.3 min were recorded at a total run time of 23 min. Assay of VLN SPL was validated as per international council for harmonization (ICH) guidelines. Average % recovery was found to be 100.04 % for VLN SPL.Conclusion: The proposed work clearly indicates that the method can be easily adapted for the routine one step estimation of VLN active pharmaceutical ingredient (API)

Surface Circulation over the Shelf Off the East Coast of India during the Southwest Monsoon

62-65V V Gopala Krishna & J S Sastry From the hydrographic data collected on board R V Gaveshani in the Western Bay of Bengal during August-September 1978, fields of temperature, salinity have been constructed and the probable flow regime has been deduced. The studies indicate strong upwelling in the southern regions off the East Coast of India. Vertical temperature and salinity structures north of Visakhapatnam show a predominant estuarine character and upwelling is not evident. In the northern regions, the flow is directed south and is consonant with that derived from wind stress curl distribution

Intrinsic fluorescence studies on saccharide binding to Artocarpus integrifolia lectin

The combining region ofArtocarpus integrifolia lectin has been studied by using the ligand-induced changes in the fluorescence of the lectin. The saccharide binding properties of the lectin show that C-l, C-2, C-4, and C-6 hydroxyl groups of D-galactose are important loci for sugar binding. The α-anorner of galactose binds more strongly than its β-counterpart. Inversion in the configuration at C-4 as in glucose results in a loss of binding to the lectin. The C-6 hydroxyl group is also presumably involved in binding as D-fucose does not bind to the lectin. The lectin binds to the Thomsen-Friedenreich antigen (Galβ(1→3)GalNAc) more strongly than the other disaccharides studied, viz. Galβ (1→4) Gal and Galβ (1→3) GlcNAc, which are topographically similar to T-antigen. This observation suggests that the combining region ofArtocarpus lectin is complementary to that of T-antigen. Solvent accessibility of the protein fluorophores have been probed by the quenching of protein fluorescence by Iodide ion in the absence and presence of sugar. In the presence of sugar a slight inaccessibility of the fluorophores to the solvent has been observed

A further study of statistics of absenteeism in Indian labour

This article does not have an abstract

Restrictive Trade Practices Policy in India.

This paper describes the restrictive trade practices policy in India. This is of recent origin, and is broadly similar to that of the United Kingdom. The registration of agreements under this legislation has provided valuable insight into the extent of restrictive trade practices. It is suggested that the failure of the act lies rather in the administration than in the provisions of the act, and its future effectiveness will depend upon the degree to which detection and enforcement are pursued. Copyright 1989 by Blackwell Publishing Ltd.

Thermohaline Circulation And Water Characteristics Around Mauritius Group Of Islands

196-200Conventional hydrocast data together with XBT soundings, collected during September-October 1987, in the area lying between 10ᵒ S to 20ᵒ S and 56ᵒ E to 62ᵒ E encompassing the Seychelles-Mauritius ridge, have been examined to project the thermohaline structure and geostrophic flow fields. In the study area, geostrophic circulation shows a predominant westerly flow. This flow on crossing the ridge zone triggers the meridional rise of isotherms towards the northern latitudes from depths of 300 to 500 m. This type of flow gives rise to possible upwelling in the western region, which is also supported by increased levels of nutrients and biomass

Thermal response of upper layers of Bay of Bengal to forcing of a severe cyclonic storm : A case study

8-11Upper ocean response to forcing of a severe cyclonic storm during May 1990 in the western Bay of Bengal was studied using the XBT data sets collected (4 d after passage of storm) under Indian TOGA programme. A maximum lowering in the sea surface temperature (SST) by 2.7-degrees-C relative to prestorm conditions and an increase in SST by 1-degrees-C during the poststorm regime of about 2 weeks were noticed close to the storm centre on the right side of the storm track. Presence of upwelling of cold water from deeper depths relative to prestorm conditions and its persistence during poststorm regime in the vicinity of the storm centre were revealed. Deep homogeneous surface layer of thickness about 55 m was developed at a distance of 110 km from the storm centre under the influence of strong winds

Analysis of dynamics and mechanism of ligand binding toartocarpus integrifolia agglutinin. A <SUP>13</SUP>C and <SUP>19</SUP>F NMR study

Binding of 13C-labeled N-acetylgalactosamine (13C-GalNAc) and N-trifluoroacetylgalactosamine (19F-GalNAc) to Artocarpus integrifolia agglutinin has been studied using 13C and 19F nuclear magnetic resonance spectroscopy, respectively. Binding of these saccharides resulted in broadening of the resonances, and no change in chemical shift was observed, suggesting that the α- and β-anomers of 13C-GalNAc and 19F-GalNAc experience a magnetically equivalent environment in the lectin combining site. The α- and β-anomers of 13C-GalNAc and 19F-GalNAc were found to be in slow exchange between free and protein bound states. Binding of 13C-GalNAc was studied as a function of temperature. From the temperature dependence of the line broadening, the thermodynamic and kinetic parameters were evaluated. The association rate constants obtained for the α-anomers of 13C-GalNAc and 19F-GalNAc (k+1=1.01×105 M−1•s−1 and 0.698 ×105 M−1•s−1, respectively) are in close agreement with those obtained for the corresponding β-anomers (k+1=0.95×105 M−1•s−1 and 0.65×105 M−1•s−1, respectively), suggesting that the two anomers bind to the lectin by a similar mechanism. In addition these values are several orders of magnitude slower than those obtained for diffusion controlled processes. The dissociation rate constants obtained are 49.9, 56.9, 42, and 43 s−1, respectively, for the α- and β-anomers of 13C-GalNAc and 19F-GalNAc. A two-step mechanism has been proposed for the interaction of 13C-GalNAc and 19F-GalNAc with A. integrifolia lectin in view of the slow association rates and high activation entropies. The thermodynamic parameters obtained for the association and dissociation reactions suggest that the binding process is entropically favored and that there is a small enthalpic contribution

Thermodynamic and kinetic studies on saccharide binding to soya-bean agglutinin.

The fluorescence of N-dansylgalactosamine [N-(5-dimethylaminonaphthalene-1-sulphonyl)galactosamine] was enhanced 11-fold with a 25 nm blue-shift in the emission maximum upon binding to soya-bean agglutinin (SBA). This change was used to determine the association constants and thermodynamic parameters for this interaction. The association constant of 1.51 X 10(6) M-1 at 20 degrees C indicated a very strong binding, which is mainly due to a relatively small entropy value, as revealed by the thermodynamic parameters: delta G = -34.7 kJ X mol-1, delta H = -37.9 kJ X mol-1 and delta S = -10.9 J X mol-1 X K-1. The specific binding of this sugar to SBA shows that the lectin can accommodate a large hydrophobic substituent on the C-2 of galactose. Binding of non-fluorescent ligands, studied by monitoring the fluorescence changes when they are added to a mixture of SBA and N-dansylgalactosamine, indicates that a hydrophobic substituent at the anomeric position increases the affinity of the interaction. The C-6 hydroxy group also stabilizes the binding considerably. Kinetics of binding of N-dansylgalactosamine to SBA studied by stopped-flow spectrofluorimetry are consistent with a single-step mechanism and yielded k+1 = 2.4 X 10(5) M-1 X s-1 and k-1 = 0.2 s-1 at 20 degrees C. The activation parameters indicate an enthalpicly controlled association process