59 research outputs found

    Biodegradable microparticulate drug delivery system of diltiazem HCl

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    The efficacy of a drug in a specific application requires the maintenance of appropriate drug blood level concentration during a prolonged period of time. Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles) over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development. The objective of this work is to prepare and evaluate diltiazem HCl loaded albumin microparticles using a factorial design. Albumin (natural polymer) microparticles were prepared by emulsion heat-stabilization method. Selected formulations were characterized for their entrapment efficiency, particle size, surface morphology, and release behavior. Analysis of variance for entrapment efficiency indicates that entrapment efficiency is best fitted to a response surface linear model. Surface morphology was studied by scanning electron microscopy. Scanning electron microscopy of the microparticles revealed a spherical, nonporous and uniform appearance, with a smooth surface. The geometric mean diameter of the microparticles was found to be 2-9 ”m, which more than 75% were below 3.5 ”m and drug incorporation efficiency of 59.74 to 72.48% (w/w). In vitro release profile for formulations containing diltiazem HCl loaded BSA microparticles with heat stabilization technique shows slow controlled the release of the drug up to 24 hours. The release pattern was biphasic, characterized by an initial burst effect followed by a slow release. All selected microparticles exhibited a prolonged release for almost 24 hours. On comparing regression-coefficient (rÂČ) values for Hixson Crowel, Higuchi and Peppas kinetic models, different batches of microparticles showed Fickian, non-Fickian, and diffusion kinetics. The release mechanism was regulated by D:P ratio. From the statistical analysis it was observed that as the drug:polymer (D:P) ratio increased, there was a significant increase in the encapsulation efficiency. Based on the particle size, entrapment efficiency and physical appearance, DTM-3 formulations were selected for in vivo release study and stability study. The in vivo result of drug loaded microparticles showed preferential drug targeting to liver followed by lungs, kidneys and spleen. Stability studies showed that maximum drug content and closest in vitro release to initial data were found in the formulation stored at 4 ÂșC. In present study, diltiazem HCl loaded BSA microparticles were prepared and targeted to various organs to satisfactory level and were found to be stable at 4 ÂșC.A eficĂĄcia terapĂȘutica de um fĂĄrmaco depende da manutenção de seu nĂ­vel plasmĂĄtico adequado em determinado intervalo de tempo. Nesse sentido, a liberação modificada de fĂĄrmacos estĂĄ disponĂ­vel em muitas vias de administração e oferece muitas vantagens (como micropartĂ­culas e nanopartĂ­culas) quando comparada Ă s formulaçÔes de liberação imediata. Essas vantagens incluem reduzida frequĂȘncia da dosagem, melhor controle terapĂȘutico e menos efeitos colaterais. Assim sendo, esses produtos apresentam maior aceitação pelos pacientes. Os avanços na ciĂȘncia dos materiais, na engenharia das partĂ­culas, em manufatura e em nanotecnologia permitiram a introdução no mercado de vĂĄrios produtos de liberação modificada e vĂĄrios outros se encontram em desenvolvimento prĂ©-clĂ­nico e clĂ­nico. O objetivo do presente trabalho foi preparar e avaliar o fĂĄrmaco cloridrato de diltiazem associado a micropartĂ­culas de albumina utilizando planejamento fatorial. As micropartĂ­culas de albumina, um polĂ­mero natural, foram preparadas por mĂ©todo de emulsĂŁo empregando estabilização por calor. As formulaçÔes selecionadas foram caracterizadas no que se refere Ă  sua eficiĂȘncia de encapsulamento, tamanho mĂ©dio de partĂ­culas, morfologia de superfĂ­cie e perfil de liberação do fĂĄrmaco. A anĂĄlise de variĂąncia relativa Ă  eficiĂȘncia de encapsulamento indicou superfĂ­cie de resposta linear. Com referĂȘncia Ă  morfologia superficial, essa foi avaliada empregando microscopia eletrĂŽnica de varredura. Essa anĂĄlise revelou micropartĂ­culas esfĂ©ricas, nĂŁo porosas e de aparĂȘncia uniforme, com superfĂ­cie lisa. O diĂąmetro mĂ©dio das micropartĂ­culas foi entre 2 e 9 ”m, sendo que mais de 75% das micropartĂ­culas se apresentaram abaixo de 3,5 ”m. AlĂ©m disso, a eficiĂȘncia de encapsulamento foi entre 59,74 e 72,48%. Quanto ao ensaio para avaliação do perfil de liberação in vitro do fĂĄrmaco associado Ă s micropartĂ­culas, as formulaçÔes apresentaram liberação lenta atĂ© 24 horas. O comportamento foi caracterizado por liberação inicial (efeito burst) seguida por liberação lenta. Todas as fĂłrmulas selecionadas apresentaram liberação prolongada por aproximadamente 24 horas. Na comparação entre os valores de coeficientes de regressĂŁo (RÂČ), os modelos propostos por Hixson Crowel, Higuchi e Peppas, para diferentes formulaçÔes de micropartĂ­culas, demonstraram cinĂ©tica de liberação de acordo com modelo Fickiano e nĂŁo-Fickiano. O mecanismo de liberação do fĂĄrmaco foi regulado pela razĂŁo entre o fĂĄrmaco e o polĂ­mero. A anĂĄlise estatĂ­stica revelou significativo aumento da eficiĂȘncia de encapsulamento quando essa razĂŁo aumentou. As avaliaçÔes relativas Ă  anĂĄlise dimensional das micropartĂ­culas, Ă  eficiĂȘncia de encapsulamento do fĂĄrmaco e Ă  morfologia permitiram a seleção da formulação DTM-3 para os ensaios de liberação in vivo e para o estudo da estabilidade. O ensaio de liberação in vivo do fĂĄrmaco associado Ă s micropartĂ­culas demonstrou sĂ­tio-alvo preferencial no fĂ­gado, seguido pelos pulmĂ”es rins e baço. No presente estudo, as micropartĂ­culas de albumina contendo cloridrato de diltiazem foram adequadamente preparadas e orientadas satisfatoriamente para vĂĄrios ĂłrgĂŁos. AlĂ©m disso, a formulação selecionada apresentou estabilidade fĂ­sico-quĂ­mica a 4 ÂșC

    Conducting Economic Evaluations Alongside Randomised Trials: Current Methodological Issues and Novel Approaches

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    Trial-based economic evaluations are an important aspect of health technology assessment. The availability of patient-level data coupled with unbiased estimates of clinical outcomes means that randomised controlled trials are effective vehicles for the generation of economic data. However there are methodological challenges to trial-based evaluations, which include the collection of reliable data on resource use and cost, choice of health outcome measure, calculating minimally important differences, dealing with missing data, extrapolating outcomes and costs over time and the analysis of multinational trials. This review focuses on the state of the art of selective elements concerning the design, conduct, analysis and reporting of trial-based economic evaluations. The limitations of existing approaches are detailed and novel methods introduced. The review is internationally relevant but with a focus towards practice in the UK

    Superhydrophobic paper in the development of disposable labware and lab-on-paper devices

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    Traditionally in superhydrophobic surfaces history, the focus has frequently settled on the use of complex processing methodologies using nonbiodegradable and costly materials. In light of recent events on lab-on-paper emergence, there are now some efforts for the production of superhydrophobic paper but still with little development and confined to the fabrication of flat devices. This work gives a new look at the range of possible applications of bioinspired superhydrophobic paper-based substrates, obtained using a straightforward surface modification with poly(hydroxybutyrate). As an end-of-proof of the possibility to create lab-on-chip portable devices, the patterning of superhydrophobic paper with different wettable shapes is shown with low-cost approaches. Furthermore, we suggest the use of superhydrophobic paper as an extremely low-cost material to design essential nonplanar lab apparatus, including reservoirs for liquid storage and manipulation, funnels, tips for pipettes, or accordion-shaped substrates for liquid transport or mixing. Such devices take the advantage of the self-cleaning and extremely water resistance properties of the surfaces as well as the actions that may be done with paper such as cut, glue, write, fold, warp, or burn. The obtained substrates showed lower propensity to adsorb proteins than the original paper, kept superhydrophobic character upon ethylene oxide sterilization and are disposable, suggesting that the developing devices could be especially adequate for use in contact with biological and hazardous materials

    Snapping shrimps of the genus Alpheus Fabricius, 1798 from Brazil (Caridea: Alpheidae): updated checklist and key for identification

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    Study of Z → llγ decays at √s = 8 TeV with the ATLAS detector

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    This paper presents a study of Z → llγ decays with the ATLAS detector at the Large Hadron Collider. The analysis uses a proton–proton data sample corresponding to an integrated luminosity of 20.2 fb−1 collected at a centre-ofmass energy √s = 8 TeV. Integrated fiducial cross-sections together with normalised differential fiducial cross-sections, sensitive to the kinematics of final-state QED radiation, are obtained. The results are found to be in agreement with stateof-the-art predictions for final-state QED radiation. First measurements of Z → llγ γ decays are also reported

    Search for leptoquark pair production decaying into te−teÂŻ + or tΌ−tÂŻÎŒ+ in multi-lepton final states in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search for leptoquark pair production decaying into te−teÂŻ + or tΌ−tÂŻÎŒ+ in final states with multiple leptons is presented. The search is based on a dataset of pp collisions at √s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. Four signal regions, with the requirement of at least three light leptons (electron or muon) and at least two jets out of which at least one jet is identified as coming from a b-hadron, are considered based on the number of leptons of a given flavour. The main background processes are estimated using dedicated control regions in a simultaneous fit with the signal regions to data. No excess above the Standard Model background prediction is observed and 95% confidence level limits on the production cross section times branching ratio are derived as a function of the leptoquark mass. Under the assumption of exclusive decays into te− (tΌ−), the corresponding lower limit on the scalar mixed-generation leptoquark mass mLQd mix is at 1.58 (1.59) TeV and on the vector leptoquark mass mU˜1 at 1.67 (1.67) TeV in the minimal coupling scenario and at 1.95 (1.95) TeV in the Yang–Mills scenario

    Software performance of the ATLAS track reconstruction for LHC run 3

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    Charged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pileup) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60 pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two

    Search for heavy Majorana or Dirac neutrinos and right-handed W gauge bosons in final states with charged leptons and jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    A search for heavy right-handed Majorana or Dirac neutrinos NR and heavy right-handed gauge bosons WR is performed in events with energetic electrons or muons, with the same or opposite electric charge, and energetic jets. The search is carried out separately for topologies of clearly separated final-state products (“resolved” channel) and topologies with boosted final states with hadronic and/or leptonic products partially overlapping and reconstructed as a large-radius jet (“boosted” channel). The events are selected from pp collision data at the LHC with an integrated luminosity of 139 fb−1 collected by the ATLAS detector at √s = 13 TeV. No significant deviations from the Standard Model predictions are observed. The results are interpreted within the theoretical framework of a left-right symmetric model, and lower limits are set on masses in the heavy righthanded WR boson and NR plane. The excluded region extends to about m(WR) = 6.4 TeV for both Majorana and Dirac NR neutrinos at m(NR) < 1 TeV. NR with masses of less than 3.5 (3.6) TeV are excluded in the electron (muon) channel at m(WR) = 4.8 TeV for the Majorana neutrinos, and limits of m(NR) up to 3.6 TeV for m(WR) = 5.2 (5.0) TeV in the electron (muon) channel are set for the Dirac neutrinos. These constitute the most stringent exclusion limits to date for the model considered
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