68 research outputs found

    Cyclodextrins and ternary complexes: technology to improve solubility of poorly soluble drugs

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    Cyclodextrins (CDs) are cyclic oligosaccharides composed of D-glucopyranoside units linked by glycosidic bonds. Their main property is the ability to modify the physicochemical and biological characteristics of low-soluble drugs through the formation of drug:CD inclusion complexes. Inclusion complexation requires that host molecules fit completely or partially within the CD cavity. This adjustment is directly related to the physicochemical properties of the guest and host molecules, easy accommodation of guest molecules within the CD cavity, stoichiometry, therapeutic dose, and toxicity. However, dosage forms may achieve a high volume, depending on the amount of CD required. Thus, it is necessary to increase solubilization efficiency in order to use smaller amounts of CD. This can be achieved by adding small amounts of water-soluble polymers to the system. This review addresses aspects related to drug complexation with CDs using water-soluble polymers to optimize the amount of CD used in the formulation in order to increase drug solubility and reduce dosage form volume.Ciclodextrinas (CDs) sĂŁo oligossacarĂ­deos cĂ­clicos, compostos por unidades D-glicopiranosĂ­dicas ligadas entre si por meio de ligaçÔes glicosĂ­dicas e sua principal propriedade estĂĄ na capacidade de alterar as caracterĂ­sticas fĂ­sico-quĂ­micas e biolĂłgicas de fĂĄrmacos com baixa solubilidade por meio da formação de complexos de inclusĂŁo fĂĄrmaco:CD. Para a formação dos complexos de inclusĂŁo a molĂ©cula hospedeira necessita ajustar-se total ou parcialmente no interior da cavidade da CD, onde este ajuste estĂĄ diretamente ligado a propriedades fĂ­sico-quĂ­micas da molĂ©cula hĂłspede e hospedeira, facilidade de alojamento da molĂ©cula hĂłspede no interior da cavidade da CD, estequiometria, dose terapĂȘutica e toxicidade. No entanto, as formas farmacĂȘuticas podem atingir um elevado volume, em função da quantidade de CD requerida, sendo necessĂĄrio aumentar sua eficiĂȘncia de solubilização para que seja possĂ­vel utilizar menores quantidades das mesmas. Isso pode ser obtido com a inclusĂŁo de pequenas quantidades de polĂ­meros hidrossolĂșveis ao sistema. Nessa revisĂŁo, sĂŁo abordados aspectos relacionados Ă  complexação de fĂĄrmacos com ciclodextrinas empregando-se polĂ­meros hidrossolĂșveis para otimização da quantidade de CD utilizada na formulação, com a finalidade de aumentar a solubilidade do fĂĄrmaco e reduzir o volume das preparaçÔes

    Measurement of the Îœe and total 8B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set

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    This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of 3He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active 8B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be 5.54-0.31+0.33(stat.)-0.34+0.36(syst.)×106 cm-2 s-1, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of Δm2=7.59-0.21+0.19×10 -5eV2 and ξ=34.4-1.2+1.3degrees

    Measurement of the gamma ray background in the Davis Cavern at the Sanford Underground Research Facility

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    Deep underground environments are ideal for low background searches due to the attenuation of cosmic rays by passage through the earth. However, they are affected by backgrounds from Îł-rays emitted by 40K and the 238U and 232Th decay chains in the surrounding rock. The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a liquid xenon TPC located within the Davis campus at the Sanford Underground Research Facility, Lead, South Dakota, at the 4,850-foot level. In order to characterise the cavern background, in-situ Îł-ray measurements were taken with a sodium iodide detector in various locations and with lead shielding. The integral count rates (0--3300~keV) varied from 596~Hz to 1355~Hz for unshielded measurements, corresponding to a total flux in the cavern of 1.9±0.4~Îł cm−2s−1. The resulting activity in the walls of the cavern can be characterised as 220±60~Bq/kg of 40K, 29±15~Bq/kg of 238U, and 13±3~Bq/kg of 232Th

    Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

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    The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

    Highly-parallelized simulation of a pixelated LArTPC on a GPU

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    The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

    MVV-Multivariate Verfahren Abschlussbericht

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    Objective of this project was the development and validation of multivariate analysis techniques for FTIR remote sensing applications. Basic research in a comprehensive manner has been performed (e.g. CLS vs. inverse methods, the background reference issue). An CLS module particularly suited for FTIR remote sensing has been developed and implemented in the data acquisition software of a commercially available FTIR instrument (K300) in order to verify the functional performance of the CLS module. The here developed multivariate algorithm has been validated during two major measurement campaigns under realistic conditions. Calibration measurements of gaseous compounds were also carried out in order to substitute commercially available spectral libraries. (orig.)SIGLEAvailable from TIB Hannover: F99B995+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman
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