Potential Drug Candidates in Clinical Trials for the Treatment of Covid-19: An Updated Overview

The coronavirus (SARS-CoV-2) emerged in December 2019 in Wuhan, China and by the end of April 2020, it spread to more than 200 countries worldwide. Particularly the USA, Brazil, Spain, Italy, France, Germany, UK, Turkey, Iran, and Russia were the most affected countries till December 2020. Currently, most of the researchers are in a continuous struggle to develop a vaccine or new drugs to combat Covid-19. There are more than 30 drug candidates including Western medicines, natural products, and traditional Chinese medicines, that have shown to exhibit some efficacy against this highly infectious virus. This review encompasses the potential efficacy of some key drugs recently tested against Covid-19.  With the rapid spread of Covid-19 reaching a new level every day, there is an immediate need to find safe and effective measures to diagnose, treat, mitigate, and combat the disease. Looking at the alarming dimensions that the disease is acquiring, treatment strategies among the different drug systems are being investigated. Currently, clinical management includes infection prevention, control measures, and supportive care, including supplemental oxygen and mechanical ventilation when indicated.  The pharmaceutical interventions evaluated for the treatment of Covid-19 include human immunoglobulin, interferons, chloroquine, hydroxychloroquine, arbidol, remdesivir, oseltamivir, favipiravir, carrimycin, methylprednisolone, bevacizumab, thalidomide, vitamin C, pyrodfenidone, darthviravir, bromexistone, ryrexavir, lopinavir, xiyanping, and traditional Chinese medicine. But still, the researchers are struggling to discover the most effective drug for the treatment of the current pandemic of Covid-19. DOI: http://dx.doi.org/10.17807/orbital.v13i4.163

Obtenção de sílica. Efeito de crômio, de temperatura e de ultra-som

Sílica contendo crômio faz parte de uma classe importante de materiais, devido às suas aplicações como catalisadores de polimerização e oxidação, fibras ópticas e pigmentos. Alta pureza e partículas uniformes determinma propriedade físicas e químicas específicas de sílica para cada aplicação. São vários os métodos propostos para preparação de sílica-crômio, sendo a precepitação um dos métodos muito utilizados..

Propriedades espectroscópicas de sílica contendo crômio

Sílica contendo crômio faz parte de uma classe importante de materiais devido às aplicações como catalisador de polimerização e de oxidação, fibras ópticas, laseres e preparação de pigmentos. Este trabalho está dividido em duas partes. A primeira refere-se ao gel úmido e seco de sílica contendo crômio. Os géis foram preparados fazendo-se a mistura das soluções de silicato de sódio solúvel (vidrolíquido) e de soluções aquosas de nitrato de crômio em pH 4 ou 9 previamente ajustado, ou em 4 após a mistura das soluções. O gel foi caracterizado por espectroscopia eletrônica de absorção no ultravioleta -visível e por microscopia eletrônica de transmissão. A morfologia dos géis de sílica e de sílica contendo crômio é dependente do valor de pH e da ordem de mistura dos reagentes. Este efeito é atribuído às espécies poliméricas do crômio diferenciadas presentes na solução que controlam a forma da partícula. Partículas esféricas podem ser obtidas pelo colapso de microgel com alto grau de ligação cruzada. A outra parte do trabalho consiste na preparação de sílica contendo crômio por dois métodos: aquecimento convencional e banho de ultra-som nas temperaturas de 50 e 80oC. O gel obtido foi tratado por extrações com soluções ácidas, extrações com água e diálise, e seco em forno de microondas. As amostras de sílica/crômio em pó foram submetidas ao tratamento térmico em temperaturas de 200 a 1400oC, com intervalos de 200oC, sob atmosfera...Chromium-containing silica belongs to an important class of materials having technological applications such as polymerization and oxidation catalyses, lasers, pigments and optical fibers. The chromium-containing silica and pure silica gels were obtained by mixing solutions of soluble sodium silicate (water glass) and chromium nitrate with adjusted pH 4 or 9 previously. Other method to prepare the gels was carried out by mixing water glass and chromium nitrate solutions and then the pH 4. The gel was characterized by ultraviolet-visible spectroscopy and transmission electron microscopic. The gel morphology is dependent on the pH value and the order of mixture of reagents. This effect is due to the nature of polymeric shape of chromium species in solution. Spherical particles can be obtained from microgel collapsing with high degree of cross linking . The second part of this work deals with powders obtained from gels. The chromium-containing silica and silica powders were obtained from gel by two methods: i) conventional heating at temperatures of 80 and 50oC and ii) sonication and heating at 80 and 50oC. The resultant colloidal silica was treated by continuous extraction acid solution in followed by extraction in distilled water and then dialyzed against distilled water and dried in microwave oven. The samples were...(Complete abstract, click electronic access below

Comparison among Different pH Values of Rhodamine B Solution Impregnated into Mesoporous Silica

We studied the behavior of different pH values of Rhodamine B solution impregnated into pores of mesoporous silica, through structural characterization techniques, such as scanning electron microscopy and porosity measurements, and spectroscopic characterization techniques, such as infrared and luminescence spectroscopy; in order to applications in luminescence. Because, Rhodamine B is an interesting xanthene dye whose optical properties depend of many factors, dye concentration and pH values. MSU-4 type mesoporous silica has been synthesized with Tween 60 surfactant as directing-structure agent and tetraethyl orthosilicate (Si(OEt)4, TEOS) as silica source. The mesoporous structures doped with dyes are promissory materials for several applications, for example, optical sensors and biomarkers.<br /

O efeito do ultra-som em reações químicas The ultrasound effect on chemistry reactions

<abstract language="eng">Unusual chemical phenomenon associated with ultrasound is on account of cavitation effect. The ultrasound increase the rate and yield of chemical reaction on account of its ability to emulsify liquids. When the ultrasound is used in metallic catalyst reaction the activity of catalyst is increased because the ultrasound clean the surface of catalyst. Sonogels have a fine porosity and large specific surface improving different properties. This paper deals with ultrasound phenomenon and gives some examples of reactions and properties where this radiation takes an important role

Comparison among different pH values of Rhodamine B solution impregnated into mesoporous silica

We studied the behavior of different pH values of Rhodamine B solution impregnated into pores of mesoporous silica, through structural characterization techniques, such as scanning electron microscopy and porosity measurements, and spectroscopic characterization techniques, such as infrared and luminescence spectroscopy; in order to applications in luminescence. Because, Rhodamine B is an interesting xanthene dye whose optical properties depend of many factors, dye concentration and pH values. MSU-4 type mesoporous silica has been synthesized with Tween 60 surfactant as directing-structure agent and tetraethyl orthosilicate (Si(OEt)4, TEOS) as silica source. The mesoporous structures doped with dyes are promissory materials for several applications, for example, optical sensors and biomarkers.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Effect of silica surface on luminescence properties of tb3+-glutamic acid.

We studied the effect of silica surface on luminescence properties of terbium complex by spectroscopy characterization, where microparticles of mesoporous silica type MSU-X was prepared. We used silica with different surface: calcined, washed, functionalized with 3- aminopropyl-triethoxysilane (APTES), and 3-glycidoxypropyl-trimethoxysilane (GPTMS); impregnated with Tb3+-glutamic acid complex. The obtained materials were characterized by scanning electron microscopy, porosity measurements, small-angle X-ray scattering, as structural characterization; Fourier transform infrared and luminescence spectroscopy, as spectroscopy characterization. Finally, we observed that functional groups at the silica surface lead to changes on luminescent properties of the final materials. The observed shift of the absorption and emission bands can be assigned to the effect of the functional groups of mesoporous silica

Electrochemical Determination of Norepinephrine by Means of Modified Glassy Carbon Electrodes with Carbon Nanotubes and Magnetic Nanoparticles of Cobalt Ferrite

This study describes the electrochemical preparation of the electrocatalytic oxidation/reduction of noradrenaline in modified glassy carbon of cobalt ferrite nanoparticles and carbon nanotubes (GC/MWCNT/FCo98). The cobalt ferrite powder was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optimum conditions found in an electrode composition were 4 &mu;L of cobalt ferrite and 10 &mu;L of carbon nanotubes in 0.1 mol L&minus;1 PBS at pH 7.0. The electrode displays electrochemical behavior in a wide potential range (&minus;0.4 to 1.0 V vs. Ag/AgCl), high conductivity, and electrode stability/durability in 0.1 mol L&minus;1 PBS. Catalytic oxidation of noradrenaline was performed at the unmodified GC electrode at +0.60 V vs. Ag/AgCl and current of 0.17 &mu;A and modified GC with cobalt ferrite nanoparticles and carbon nanotubes at +0.54 V vs. Ag/AgCl and current of 0.23 mA. With regard to the anodic peak current (Ipa) versus noradrenaline concentration by means of the amperometric method at the modified electrode, (which is linear in the 0.16 and 1.91 mmol L&minus;1 concentration range), the concentration limit was 0.76 &mu;mol L&minus;1. In this way, the modified electrode GC/MWCNT/FCo98 was found to be a promising application for the determination of this neurotransmitter in the area of neuroscience