FORMULATION AND EVALUATION OF VALSARTAN FAST DISINTEGRATING TABLETS BY VACUUM DRYING TECHNIQUE

ABSTRACTObjective: The main objective present research work an attempt has been made to prepare fast dissolving tablets of Valsartan by using vacuumdrying technique. Camphor, Urea and Menthol are used as a sublimating agent. Valsartan is an oral antihypertensive agent, with problems of variablebioavailability and bioequivalence related to its poor water solubility. Valsartan is an angiotensin II type 1 receptor antagonist indicated in thetreatment of hypertension. Methods: The prepared tablets Valsartan fast dissolving tablets were evaluated for various parameters like weight variation, hardness, friability,disintegration time, drug content, water absorption ratio, wetting time, in- vitro drug release, FTIR, DSC studies and short term stability studies. Theblend was examined for the pre-compressional and post-compressional parameter. Results and Discussions: The values of pre-compression parameters evaluated were within prescribed limits and indicated good free flowingproperty. All the post-compressional parameter are evaluated were prescribed limits and results were within IP acceptable limits. Based on the invitrodisintegrationtime and dissolution studies formulationsSC2 andSC3werefoundtobe promisingandshowedadisintegrationtime of 24secand16 secrespectively.FormulationSC3 containingcamphor showedhighestdrug release99.4% within10 min.IR spectralanalysisandDSC studyshowedthattherewasno drug interactionwith formulationadditivesofthetablet asthereis novariationand shift inthe position ofcharacteristicabsorptionbands it canbejustifiedthereis no interactionbetweendrug and polymer.Short termstability studieson the formulationsindicatedthatthereareno significant change in hardness,friability,drug contentand in-vitrodrug release(p<0.05). Conclusion: The results concluded that fast dissolving tablets of Valsartan showing enhanced dissolution may lead to improved bioavailabilityand effective therapy by using sublimation method.Keywords: Fast dissolving tablet, Valsartan, Crospovidone, Camphor, Urea, Disintegration time

Enhanced magnetization and improved insulating character in Eu substituted BiFeO3

The polycrystalline Bi1-xEuxFeO 3 (x=0, 0.05, and 0.1) ceramics were synthesized by conventional solid-state route. X-ray diffraction studies and Raman measurements revealed that the compounds crystallized in rhombohedral structure with R3c space group. In addition, a nominal percentage of orthorhombic phase was observed in 10 mol.% Eu substituted BiFeO3. Appearance of weak ferromagnetism and significant increase in Néel temperature TN in the substituted compounds were discussed on the basis of structural distortions. Enhanced remnant magnetization of 75 memu/g and large coercive field of 6.4kÖe were observed in 10 mol.% Eu substituted BiFeO3. Equivalent circuit model was employed to estimate the grain and grain boundary contributions towards the electrical parameters such as resistance and conductivity. Non-Debye type of relaxation was confirmed from impedance and electric modulus studies. The obtained frequency variation of ac conductivity at different temperature obeys Jonscher's power law and is consistent with the correlated barrier hopping model. Temperature variations of ac conductivity explained that electronic hopping, oxygen vacancies movement, and/or creation of defects contribute to conduction in all the compounds

Carrier Frequency Offset Estimation Algorithm in the Presence of I/Q Imbalance in OFDM Systems

In this paper, we analyzed the feasibility of using a virtual carrier based carrier frequency offset estimation algorithm in the presence of I/Q imbalance in OFDM systems. Based on the analysis of the signal model with both receiver CFO and I/Q imbalance impairment we conclude that it is feasible to extending the virtual carrier based CFO estimation algorithm to the I/Q imbalance scenario. The CFO estimation performance is evaluated through computer simulation. Impact of parameters on the estimation performance is investigated and it is consistent with our analysis. After CFO correction, a blind based I/Q imbalance estimation and compensation algorithm is applied. The final detection performance demonstrates that the virtual carrier based CFO estimation performance is good enough for subsequent I/Q imbalance estimation and compensation

NON-HEPATIC HYPERAMMONEMIC COMA: A CASE REPORT

ABSTRACTWhile the most common cause of hyperammonemic (HA) coma is hepatic disorder, other rare etiologies to be considered include congenital causes,drug induced states, portosystemic shunts, and urinary tract infections with urea-splitting organisms. HA usually results from one of the followingthree mechanisms: A relative excessive nitrogen load on a normal functioning liver via the portal circulation (e.g., parenteral nutrition in a patientwith urea cycle defect); ammonia bypassing liver (e.g., congenital vascular malformations, portal hypertension in cirrhotic patients); or from impairedammonia metabolism. Herein, we describe a case of HA coma secondary to an interplay of multiple psychiatric drugs mainly sodium valproate andprobably an added effect by the lithium-induced hypothyroidism/myxedema.Keywords: Drug-induced, Hyperammonemia, Lithium, Myxedema, Valproic acid

Text Categorization and Machine Learning Methods: Current State Of The Art

In this informative age, we find many documents are available in digital forms which need classification of the text. For solving this major problem present researchers focused on machine learning techniques: a general inductive process automatically builds a classifier by learning, from a set of pre classified documents, the characteristics of the categories. The main benefit of the present approach is consisting in the manual definition of a classifier by domain experts where effectiveness, less use of expert work and straightforward portability to different domains are possible. The paper examines the main approaches to text categorization comparing the machine learning paradigm and present state of the art. Various issues pertaining to three different text similarity problems, namely, semantic, conceptual and contextual are also discussed

Hydrodynamic Performance and Acoustic Response of Ship Propeller

The aim of the paper is to predict the hydrodynamic performance and noise generated by the propeller at different advance ratio and the speed of the propeller. Three bladed, DTMB 4119 propeller model was created using the NACA66 modified line, a = 0.8 hydrofoil profile. ANSYS Workbench software is used for mesh generation and computational analysis. A large-eddy simulation turbulence model and Ffowcs Williams-Hawkings (FWH) acoustic model is used for all simulations. A moving reference frame is used to simulate the rotational effects of the propeller. The speed of the propeller is 792 rpm, the propeller being 0.2 m, and inlet velocity is varied to study the effect of the advance ratio. A transient analysis is carried out using a time step value of 0.0005 seconds and the total simulation time is 0.6 seconds. The hydrodynamic performance parameters are validated by comparing with the experimental data available in the literature. The sound pressure level (SPL) is plotted over the frequency range of 0 to 1000 Hz at different locations, speed, and an advance ratio of 0.5, 0.7, 0.833, and 0.9,1. The structural, acoustic and hydrodynamic behaviour of the propeller was predicted using a two-way fluid structure interaction at an advance ratio of 0.833. The major conclusions drawn from the analysis are that the sound pressure level values are increased at the propeller off-design conditions and varying with the receiver locations. The data generated from this study is useful for the designers to carry out further research in order to reduce the noise generated from the propeller

Contribution of N₂O emissions to the atmosphere from Indian monsoonal estuaries

Estuaries are known to contribute a significant amount of nitrous oxide (N2O) to the atmosphere; however, the contribution from the Indian estuaries is unknown. We made an attempt to estimate emissions of N2O from the Indian estuaries by collecting samples from 28 major and minor estuaries along the Indian coast during the wet and dry periods. The N2O was mostly saturated in all measured Indian estuaries during the study period (72–631 %), with exceptionally high saturation in the Ponniyaar estuary (5902%) during the wet period. The N2O saturation displayed a strong relation with dissolved inorganic nitrogen (DIN; nitrate+nitrite and ammonium), ammonium and dissolved oxygen saturation, suggesting that nitrification is the major source of N2O in the Indian estuaries. The negative relation between salinity and N2O saturation suggests inner estuaries are a strong source compared to outer estuaries. The annual mean N2O saturation (204 ± 137%) and fluxes (1.3 μmol N2O m−2 d−1) in the Indian estuaries were significantly less than European estuaries (271% and ∼2.7 μmol N2O m−2 d−1, respectively). The estimation of flux of N2O from the European estuaries was also biased due to the inclusion of an exceptionally high supersaturation value from a small UK estuary, Colne (2645%). However, low N2O saturation and fluxes in the Indian estuaries were related to mean low concentration of DIN that led to low nitrification rates compared to world estuaries. Despite India ranking second in artificial fertilizers use, high flushing rates during the wet period reduce residence time leading to less modification within the estuary