In vitro Release kinetics and Bio availability of Layered Matrix tablets of Diclofenac Sodium

Controlled release tablets having near zero-order release of diclofenac sodium water soluble drug were prepared using guar gum (GG) in matrix core and Hydroxy Propyl Cellulose (HPC), Hydroxy Propyl Methyl Cellulose (HPMCK4M) and Sodium Carboxy Methyl Cellulose (Na CMC) as barrier layers. The optimum ratio of drug: guar gum was found to be 1:1, anionic GG in the matrix core and anionic Na CMC as barrier layers resulted in near zero order release of diclofenac sodium. Different dissolution models were applied to drug release data in order to evaluate release mechanisms and kinetics. The nature of drug release from matrix tablets and layered matrix tablets followed non-Fickian diffusion and super case II mechanism respectively. Mean dissolution time (MDT) for the formulations MT-GG and MLT-06 were found to be 3.65h and 16.57h, while Dissolution Efficiency (DE8%) decreases, indicating that the release of drug is slower from layered matrix tablets. On the basis of in vitro release data, MLT-06 was subjected to bioavailability studies. The in-vivo characterization of diclofenac sodium in human volunteers from formulation MLT-06 showed delayed Tmax unaltered bio availability indicating a slow and controlled release of the drug from layered matrix tablets.Keywords: Diclofenac sodium, Matrix and layered matrix tablets, Controlled released

Phase stability and mechanical property of γ′- (Ni1-xCox)3Al1-yCry alloys

The phase stability and mechanical property of γ ′-(Ni _1-x Co _x ) _3 Al _1-y Cr _y phase of Ni-Co based superalloys are studied by the first-principles method. The calculated mixing enthalpies at 0 K indicate that the alloys are thermodynamically unstable against phase separation into Ni _3 AlCr and Co _3 AlCr alloys. Additions of 6.25 at % of Cr into (NiCo) _3 Al alloy can decrease the positive mixing enthalpy by 34%, hence Cr has a significant stabilizing effect on γ ′ phase. The configurational entropy can further stabilize the alloy at finite temperature. A strong tetragonal shear softening is observed for (Ni _1-x Co _x ) _3 Al _1-y Cr _y alloys with large Co concentration. Cr additions could increase C ′ of the alloys, and thus offset the softening effect of Co by a certain extent. The electronic density of states analysis demonstrates that the flexibility of Al p band and synergistic alloying effect are the physics behind the stabilization the γ ′ phase of Ni-Co based superalloy by Cr alloying

Evaluation of anti-allergic activity of gossypin and suramin in mast cell-mediated allergy model

90-95The mast cell-mediated allergic reactions are involved in many allergic diseases, such as asthma, allergic rhinitis and sinusitis. Stimulation of mast cells initiates the process of degranulation, resulting in the release of mediators such as histamine and an array of inflammatory cytokines. In this report, we investigated the effect of gossypin (a biflavonoid) and suramin (a synthetic polysulphonated naphtylurea) on the mast cell-mediated allergy model, and studied the possible mechanism of their action. Both gossypin and suramin inhibited (P<0.001) compound 48/80-induced systemic anaphylaxis reactions, antiprurities (P<0.001) and reduced the histamine release in rats. Further, both showed significant (P<0.001) protection against rat peritoneal mast cells activated by compound 48/80. Thus, our findings provide evidence that gossypin and suramin inhibit mast cell-derived allergic reactions.</b

Evaluation of antiulcer activity of Boswellia serrata bark extracts using aspirin induced ulcer model in albino rats

The effect of bark extracts of Boswellia serrata (Family Bursera-ceae) was evaluated in aspirin induced ulceration (200mg/kg) in albino rats. Antiulcer activity was evaluated by measuring ulcer index and percentage of ulcer healing. The petroleum ether (250mg/kg) and aqueous extracts (250mg/kg) of bark of Boswellia serrata plant showed significant antiulcer activity as evidenced by the data obtained. Histopathological findings also confirm the anti-ulcer activity of Boswellia serrata bark extracts in albino rats

Dirac points and flat bands in two-dimensional magnonic crystals with honeycomb–kagome structure

Based on the model of magnonic crystals (MCs) with honeycomb structure, we propose another model of two-dimensional MCs with honeycomb–kagome structure that is a periodic magnetic composite system composed of Fe, Co, or Py ferromagnetic cylindrical scatterers arranged in the EuO matrix as the honeycomb–kagome structure. The band structures of magnons in these systems are studied numerically by using the plane-wave expansion method. The results show that the Dirac points of magnons will be generated at the Brillouin region points if the scatterers are close-packed, that is to say, the edges of cylindrical scatterers are in contact with each other. The frequency of Dirac points can be indirectly adjusted by changing the radius ratio of close-packed cylinders. In addition, in the case of a large difference in the radius between the close-packed cylindrical scatterers, there will be a magnonic flat band in the band structure, which is a phenomenon of so-called compact localized states different from the impurity state in the crystal, and it is formed by the highly interference superposition of spin waves in the honeycomb–kagome structure. The research on the generation and modulation of magnonic Dirac points and flat bands not only expands the research content of condensed matter topological physics but also provides a promising platform for the application of artificial MCs in the fabrication of spin-wave topological devices

Correlation between deformation and total entropy change at the first-order magnetic transition of Fe2P-based magnetocaloric materials

While there is a growing consensus that lattice is an important source of entropy change at structural or elastic first-order magnetic transitions (FOMT) with finite volume change, the case of volume preserving transitions (ΔV = 0) remains more controversial. Here, the evolution of the total transition entropy change within the Fe2P family is presented as a function of the discontinuity on the ratio of the cell parameters. A striking correlation between ΔStr and Δ(c/a) is observed. This relationship is a first step towards a systematization of the FOMT properties in the Fe2P materials system. It also demonstrates that deformation can play a leading role in volume preserving FOMT

Free radical scavenging activity of gossypin and nevadensin: An in-vitro evaluation

Objectives: The antioxidant potential of gossypin and nevadensin, two flavonoid compounds, were evaluated by in vitro methods. Materials and Methods: Gossypin, nevadensin, and the reference standard, butylated hydroxyl toluene (BHT), were evaluated for DPPH (1, 1-diphenyl-2-picrylhydrazyl), nitric oxide, superoxide, and hydroxyl radical scavenging activity. Results: Gossypin and BHT showed the potential for significant DPPH radical inhibition of up to 88.52 and 91.45% at 100 µg/ml concentration. With a 100 µg/ml concentration of gossypin, the in vitro nitric oxide, superoxide, and hydroxyl radical scavenging activity was found to be 74.00, 74.22, and 67.15%, respectively; and with 100 µg/ml of BHT the corresponding values were 82.24, 81.76, and 73.03% of inhibition, respectively. Conclusion: The study results showed that gossypin has significant antioxidant activity