Norberto Aranha

Porosity measurement of solid pharmaceutical dosage forms by gamma-ray transmission

The aim of the present work is the determination of porosity in tablets by using the gamma-ray transmission technique. Tablet dissolution depends on some inherent characteristics of the manufacturing process, such as compression force, tablet volume, density and porosity, nature of excipients, preparation methods and its physical-chemical properties. Porosity is a measure of empty spaces in a material and can be determined by various techniques. In this paper, we propose the use of a gamma-ray transmission technique to obtain the porosity of experimental formulation of tablets. The results of porosity were compared with those obtained by using conventional methodology (density and mercury intrusion). The experimental setup for gamma-ray transmission consists of a gamma-ray source of (241)Am (photons of 59.6 keV and an activity of 3.7 × 10(9)Bq), an NaI(Tl) scintillation detector, collimators and a standard gamma-ray spectrometry electronics. Our results suggest that the gamma-ray transmission technique is a powerful tool for non-destructive porosity quantification of solid pharmaceutical forms and presents smaller errors than those obtained with conventional methodologies.

Supercritical fluid and pharmaceutical applications. Part I: Process classification

The supercritical fluid technology has been target of many pharmaceuticals investigations in particles production for almost 35 years. This is due to the great advantages it offers over others technologies currently used for the same purpose. A brief history is presented, as well the classification of supercritical technology based on the role that the supercritical fluid (carbon dioxide) performs in the process. Key words: Supercritical fluid technology, supercritical carbon dioxide, pharmaceuticals.

Study of the elemental composition of saliva of smokers and nonsmokers by X-ray fluorescence

Cigarette smoking is a serious public health problem. According to data from the World Health Organization, it is estimated that currently more than 1.2 billion people worldwide do tobacco use and that smoking-related diseases are responsible for about 6 million deaths each. With attention to this, it is necessary to seek preventive and prognostic of trying to reduce these numbers and alert the public in general about the danger and the harm caused by its use. Thus, the objective of the research work undertaken was to evaluate and compare the chemical composition of collected saliva samples of smokers and nonsmokers by X-ray Fluorescence analyses. 32 individuals were selected, 16 of which used cigarette on a daily basis and the other 16 had never smoked. Saliva was collected with the help of a (sterile) disposable Pasteur pipette and samples sent to the Applied Nuclear Physics Laboratory at UNISO (LAFINAU), where analyzes were carried out. Individuals who agreed to participate in the study answered a questionnaire to define their profile of inclusion and signed an informed consent form (CEP Protocol no. 831.753 of 09/10/2014). The results clearly showed that there are differences in the concentrations of chemical elements in the saliva of smokers and non-smokers. The biggest discrepancies were found at concentrations of the chemical elements Sulfur, Phosphorus, Chlorine and Potassium, and smaller differences in the concentration of the elements Calcium, Manganese, Iron, Copper, Titanium, Vanadium and Nickel. In only one saliva sample, and in quite low amounts, arsenic was detected. The results indicate that smoking produces more significant changes in the saliva of women than in men, increasing the concentration of some elements in the saliva of female smokers, much more than in the male smokers. The cigarette usage time also appears to exert a greater influence on the composition of the saliva of women than in men, indicating that the damage caused by cigarette use may in fact be higher in women than in men.

ESTUDO SOBRE A VIABILIDADE TÉCNICA E ECONÔMICA DA RECICLAGEM DE ENTULHO PARA A PRODUÇÃO DE CONCRETO EM OBRAS CIVIS.

Os residuos solidos gerados pela construcao civil e demolicoes (RCDs) vem aumentando e tem sido motivo de preocupacoes com os impactos ambientais e urbanos. Consequentemente, tem havido esforcos crescentes no reaproveitamento destes RCDs. Uma linha de estudos que vem sendo conduzida refere-se a reutilizacao do entulho, transformando-o em agregados para concreto, argamassas e pavimentacao, por meio de britagem. Neste trabalho, foram produzidos tracos de concreto originado de material usinado (usado como referencia FCK = 25 Mpa) e comparando-os com tracos nos quais foram seletivamente empregados materiais reciclados (areia, brita e pedrisco), mantendo-se a proporcao de cimento e aditivo. Testes de slump e de compressao foram realizados nas amostras destes tracos, como tambem avaliados os respectivos custos de producao. Concluiu-se que nem sempre o de menor custo atende aos requisitos de resistencia.

A lei de Hooke e as molas não-lineares, um estudo de caso

Neste trabalho pretende-se analisar elementos elasticos com respostas linear e nao linear. Foi realizado o estudo comparativo entre tres molas helicoidais, sendo uma linear e duas nao lineares, e um tubo de latex. O estudo envolveu o levantamento das curvas de forca versus distância e seus respectivos ajustes matematicos para cada elemento elastico. A proposta e apresentar diferentes formas de abordar o tema elasticidade nas aulas de fisica, visando chamar a atencao do aluno de que a linearidade que trata a lei de Hooke aplica-se apenas para uma pequena faixa de valores de forca e que em varias situacoes os elementos elasticos tem um comportamento nao linear, sendo necessario lancar mao de outras relacoes matematicas que se ajustem aos dados experimentais.

Aparato educacional para estudo da queda livre com análise do movimento

This paper presents an experimental project for the electronic measurement of free falling objects for educational purposes. The apparatus consists of a PVC pipe, within which the objects are released. Switching sensors were placed inside the tube at regular distances. Objects passing through them trigger a signal, which is collected, processed by the Arduino platform and sent via serial port to a XBEE module. This send data remotely to another XBEE module attached to a USB port in a computer, where a program calculates the acceleration of movement and serves as user interface. An original solution was devised to avoid interference among sensors. As case study, measures of the gravitational acceleration were made with objects of different geometries. Models with and without air resistance were employed and drag coefficient was obtained.

Deformulation of a solid pharmaceutical form using computed tomography and X-ray fluorescence

Deformulation of medicines is of undeniable importance, since it can be utilized both to unravel the chemical composition of the excipients integrating a pharmaceutical formulation of a specific medicine and as an important tool to conduct morphometric studies of the formulation under study. Such strategy may be utilized in analytical studies aiming at quantifying the components of reference drugs, or in the identification of putative counterfeit pharmaceuticals. Deformulation makes use of physicochemical analysis tools to characterize, from the chemical point of view, the components integrating medicine pharmaceutical formulations and from the physical point of view, the morphological part of the pharmaceutical formulation. The techniques of computer tomography (SkyScan 1174 - Bruker microCT) and X-ray fluorescence analyses (using an X-ray source with W-anode from Hammatsu Photonics and Silicon Drift detector from Amptek) were successfully used in performing a process of deformulation of a solid pharmaceutical formulation of tablets, utilized herein as a model medicine for controlled drug release. The analytical methods used in this work, proved their effectiveness for the main goal of this study, which aimed to characterize a pharmaceutical formulation via its deconstruction.