DISSOLUTION ENHANCEMENT OF POORLY WATER-SOLUBLE DRUG BY CYCLODEXTRINS INCLUSION COMPLEXATION

Objective: Solubility of a drug is an important property that mainly influences the extent of oral bioavailability. Enhancement of oral bioavailability of poorly water-soluble drugs is the most challenging aspects of drug development. It is very important to find appropriate formulation approaches to improve the aqueous solubility and bioavailability of poorly aqueous soluble drugs. Ezetimibe is a new lipid lowering agent in the management of hypercholesterolemia. The drug is water-insoluble, lipophilic, and highly permeable according to the pharmaceutical classification system. Therefore, the bioavailability of ezetimibe may be improved by increasing its solubility. Methods: In present work solubility of ezetimibe was increased with inclusion complexes by a different technique like physical mixture, co-grinding and modified kneading method. The physical properties of the prepared inclusion complex of ezetimibe were characterised by Differential scanning calorimetry (DSC), X-ray diffraction spectroscopy (XRD), Fourier transform infra-red spectroscopy (FTIR) and in vitro dissolution studies. Results: From the dissolution studies of ezetimibe with HP-β-cyclodextrin(1:1 and 1:2), we conclude that the prepared complexes of ezetimibe with HP-β-cyclodextrin (1:2) by modified kneading method showed higher release i.e. 88.35% in 60 min. than in (1:1) 76.75% in 60 min. So, ezetimibe with HP-β-cyclodextrin (1:2) inclusion complex was used to formulate tablet by direct compression method. Conclusion: From the dissolution data of formulated tablets was observed that drug release was more in tablet dosage form as compared to plain ezetimibe and especially formulation in a ratio of 1:2 was found the promising result. Also from one-month stability data shows no significant change compared to the initial result

Using Nanocavity Plasmons to Improve Solar Cell Efficiency

Although in principle very promising, photovoltaic technology has so far failed to deliver robust high efficiency modules at affordable prices. Despite considerable research, high efficiency silicon based cells remain expensive, while the more recent organic photovoltaics are still struggling with low efficiencies and short lifetimes. Meanwhile, over the last few years, the study of localized plasmons [1,2] has also received great attention due to the high field enhancements associated with confined fields , with a wide range of applications possible, from optical switches to substrates for surface enhanced Raman spectroscopy (SERS). Here we discuss how combining the structures normally used in photovoltaic devices with metallic cavities supporting localized plasmons can lead to considerable improvements in the performance of solar cells. In particular we show how by changing the shape and size of spherical voids on a metallic surface, one can tune the plasmon modes to obtain significant absorptions across the solar spectrum [3]. By coating one such nanocavity surface with a sub 100 nm-layer of semiconductor, we can create a nanostructured solar cell, where the localised Mie modes efficiently couple light into the semiconductor layer. As the plasmons electric field enhancement is largest very close to the surface, significant absorption can be maintained even when the semiconductor thickness is reduced to below the typical exciton diffusion length. In addition minority carrier transport is improved. That means we can beat the usual balance between light absorption and exciton recombination loses, and so significantly increase the overall efficiency of the photovoltaic devices. Keywords: plasmons, solar cells, nanostructured surfaces

Collapse Dynamics of a Star of Dark Matter and Dark Energy

In this work, we study the collapse dynamics of an inhomogeneous spherically symmetric star made of dark matter (DM) and dark energy (DE). The dark matter is taken in the form of a dust cloud while anisotropic fluid is chosen as the candidate for dark energy. It is investigated how dark energy modifies the collapsing process and is examined whether dark energy has any effect on the Cosmic Censorship Conjecture. The collapsing star is assumed to be of finite radius and the space time is divided into three distinct regions $\Sigma$ and $V^{\pm}$, where $\Sigma$ represents the boundary of the star and $V^{-}(V^{+})$ denotes the interior (exterior) of the star. The junction conditions for matching $V^{\pm}$ over $\Sigma$ are specified. Role of Dark energy in the formation of apparent horizon is studied and central singularity is analyzed.Comment: 13 page

Formulation Development and Evaluation of Aqueous Injection of Poorly Soluble Drug Made by Novel Application of Mixed Solvency Concept

It is commonly recognized in the pharmaceutical industry that on average more than 40% of newly discovered drug candidates are poorly water-soluble. The objective of present research is to explore the application of mixed solvency technique in the injection formulation of poorly soluble drugs and to reduce concentration of individual solubilizers (used for solubility enhancement) to minimize the toxic effects of solubilizers. In the present work poorly soluble drugs Ofloxacin are selected as model drugs. Ofloxacin is an antibiotic drug tried to formulate the aqueous injection by the use of various physiologically compatible solubilizing agent like Lignocaine Hydrochloride, Niacinamide, Sodium benzoate, Sodium citrate, PEG 400, PEG 4000, PVP 40000, Ethanol, and Propylene Glycol. For expected synergistic enhancement effect on solubility of these poorly soluble drugs various blends of solubilizers shall be tried to decrease the amounts of Solubilizer employed for a desired solubility enhancement ratio. The study further opens the chances of preparing dry powders for injection of drug which are not stable in aqueous solution, ready to use injection. Key word- Mixed solvency solubilization, Ofloxacin, solubility enhancement, synergistic enhancement effect

Unitarity constraints on the stabilized Randall-Sundrum scenario

Recently proposed stabilization mechanism of the Randall-Sundrum metric gives rise to a scalar radion, which couples universally to matter with a weak interaction ($\simeq 1$ TeV) scale. Demanding that gauge boson scattering as described by the effective low enerrgy theory be unitary upto a given scale leads to significant constraints on the mass of such a radion.Comment: 10 page Latex 2e file including 4 postscript figures. Accepted in Journal of Physics

An outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in dermatology indoor patients

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen. Indiscriminate and increased use of systemic antibiotics has led to the emergence of MRSA. Infected or colonized ward patients are the main reservoir of infection. Once colonized, the risk of subsequent local and systemic infections is high, especially in the elderly, and in debilitated and immunosuppressed patients. Methods: We report an outbreak of MRSA in the dermatology ward of a tertiary care hospital and describe measures taken to control it. Results: Ten patients were found to be MRSA positive over a span of three months while screening swabs from wet lesions in indoor patients. On the basis of risk assessment, they were treated with appropriate systemic and topical therapy. One patient died while the remaining nine patients showed a good response to therapy. All the MRSA isolates were found to be sensitive to vancomycin, teicoplanin and linezolid. Conclusion: This is the first case report of MRSA infection in dermatology indoor patients in India

Mass-Enhanced Fermi Liquid Ground State in Na1.5_{1.5}Co2_2O4_4

Magnetic, transport, and specific heat measurements have been performed on layered metallic oxide Na$_{1.5}$Co$_2$O$_4$ as a function of temperature $T$. Below a characteristic temperature $T^*$=30$-$40 K, electrical resistivity shows a metallic conductivity with a $T^2$ behavior and magnetic susceptibility deviates from the Curie-Weiss behavior showing a broad peak at $\sim$14 K. The electronic specific heat coefficient $\gamma$ is $\sim$60 mJ/molK$^2$ at 2 K. No evidence for magnetic ordering is found. These behaviors suggest the formation of mass-enhanced Fermi liquid ground state analogous to that in $d$-electron heavy fermion compound LiV$_2$O$_4$.Comment: 4 pages, 4 figures, to be published in Phys. Rev. B 69 (2004