Use of solid dispersions to increase stability of dithranol in topical formulations

Este trabalho teve como objetivo aumentar a estabalidade do ditranol através da preparação de dispersões sólidas (DS). Prepararam-se duas DS diferentes em proporção de 1:9 de ditranol/excipiente: em uma das DS utilizou-se beenato de glicerila como excipiente e na outra se utilizou mistura de óleo de argan com ácido esteárico (razão 1:8). Posteriormente, efetuou-se a incorporação de ditranol puro e das DS contendo este fármaco num creme hidrófilo ou óleo-água (O/A) e em pomada hidrófoba, na proporção 1:10 (fármaco ou respetivas DS/base dermatológica). As propriedades físicas e mecânicas das formulações semissólidas incorporando fármaco ou as respetivas DS previamente desenvolvidas, foram avaliadas através da análise do comportamento reológico e das propriedades de textura. Para avaliar a estabilidade, os parâmetros do espaço de cor L*a*b* das DS e das formulações semissólidas e o pH das preparações hidrófilas foram determinados em períodos de tempo definidos, durante um mês para cada amostra armazenada sob diferentes condições, especificamente, exposição à luz (à temperatura ambiente), protegidas da luz à temperatura elevada (37 °C) e protegidas da luz (temperatura ambiente). Embora tenham apresentado valores de firmeza e de adesividade mais elevados, as pomadas hidrófobas apresentaram melhores características reológicas do que os cremes óleo-água. Além disso, as pomadas hidrófobas também apresentaram melhor estabilidade, com pequenas alterações nos parâmetros do espaço de cor L*a*b*. Os resultados deste trabalho permitiram concluir que as DS desenvolvidas contribuíram para o aumento da estabilidade do ditranol.The present study was planned to improve the stability of dithranol using solid dispersions (SD). Two different SD at a 1:9 ratio of dithranol/excipient were prepared: one of them using glyceryl behenate as excipient and the other using a mixture of argan oil with stearic acid (1:8 ratio) as excipient. Pure dithranol and SD of dithranol were incorporated in an oil-in-water cream and in a hydrophobic ointment in a drug/dermatological base ratio of 1:10. The physical and mechanical properties of semisolid formulations incorporating the pure drug and the developed SD were evaluated through rheological and textural analysis. To evaluate the stability, L*a*b* color space parameters of SD and semisolid formulations, and pH of hydrophilic formulations were determined at defined times, during one month. Each sample was stored at different conditions namely, light exposure (room temperature), high temperature exposition (37 °C) (protected from light) and protected from light (room temperature). Despite higher values of firmness and adhesiveness, hydrophobic ointment exhibited the best rheological features compared to the oil-in-water cream, namely a shear-thinning behavior and high thixotropy. These formulations have also presented more stability, with minor changes in L*a*b* color space parameters. The results of this study indicate that is possible to conclude that the developed SD contributed to the increased stability of dithranol

EVOLUTION OF LIPOSOMAL CARRIERS INTENDED TO ANTICANCER DRUG DELIVERY: AN OVERVIEW

Most current anticancer agents are present lack of specificity, leading to systemic toxicity and adverse effects, and limiting the maximum dose of drug. Liposomes quickly passed from a simple scientific curiosity to magic bullets†for the delivery of drugs. Liposomal formulations of anticancer drugs have been extensively evaluated, with notorious advances and the market introduction of some of them. In the last years, the research under liposomes has been carried out to increase the circulation time and the specificity to cancer cells. The aim of this work was to make a review about the research carried out about the application of liposomes as carriers for anticancer drugs. Liposomal formulations of anticancer drugs have been extensively evaluated. However, many other liposome based carriers were studied, like immuno liposomes, thermossensitive liposomes, dual functional liposomes and cross linked multifunctional liposomes, intended to increase drug specificity. Additionally, some special types of liposomes, like niosomes, transfersomes and ethosomes were also investigated as cytotoxic drug carriers

EVOLUTION OF LIPOSOMAL CARRIERS INTENDED TO ANTICANCER DRUG DELIVERY: AN OVERVIEW

Most current anticancer agents present lack of specificity, leading to systemic toxicity and adverse effects, and limiting the maximum dose of drug. Liposomes quickly passed from a simple scientific curiosity to magic bullets†for the delivery of drugs. Liposomal formulations of anticancer drugs have been extensively evaluated, with notorious advances and the market introduction of some of them. In the last years the research under liposomes has been carried out to increase the circulation time and the specificity to cancer cells. The aim of this work was to make a review about the research carried out about the application of liposomes as carriers for anticancer drugs. Liposomal formulations of anticancer drugs have been extensively evaluated. However, many other liposome based carriers were studied, like immunoliposomes, thermossensitive liposomes, dual functional liposomes and crosslinked multifunctional liposomes, intended to increase drug specificity. Additionally, some special types of liposomes, like niosomes, transfersomes and ethosomes were also investigated as cytotoxic drug carriers

Densidade mineral óssea e actividade física na Universidade Fernando Pessoa

O objectivo do estudo foi estimar a densidade mineral óssea e a actividade física na comunidade da Universidade Fernando Pessoa. Foram avaliados 164 indivíduos dos 17 aos 81 anos (118 do sexo feminino e 46 do sexo masculino) entre estudantes, docentes e funcionários da Universidade Fernando Pessoa, no âmbito do Projecto Ambulatório de Saúde Oral e Pública desta Universidade, através de desnitometria óssea por ultrassons. Os parâmetros de t-score e densidade mineral óssea revelaram-se, de uma forma geral, normais. Contudo é necessário atender ao facto de a amostra em análise ser ainda jovem e pouco activa, pelo que no futuro estes valores poderão tornar-se o espelho da osteoporose. The main purpose of this study was to estimate the bone mineral density in the community of University Fernando Pessoa. There were evaluated 164 subjects with ages from 17 until 81 years old (118 females and 46 males) involving students, teachers and workers of the University Fernando Pessoa, during the Ambulatory Project of Oral and Public Health, by ultrasound densitometry. The parameters of t-score and bone mineral density were generally normal. However it is necessary to consider that this sample was young and not very active, so in the future these results could become a mirror for osteoporosis

Characterization and stability studies of emulsion systems containing pumice

Emulsions are the most common form of skin care products. However, these systems may exhibit some instability. Therefore, when developing emulsions for topical application it is interesting to verify whether they have suitable physical and mechanical characteristics and further assess their stability. The aim of this work was to study the stability of emulsion systems, which varied in the proportion of the emulsifying agent cetearyl alcohol (and) sodium lauryl sulfate (and) sodium cetearyl sulfate (LSX), the nature of the oily phase (decyl oleate, cyclomethicone or dimethicone) and the presence or absence of pumice (5% w/w). While maintaining the samples at room temperature, rheology studies, texture analysis and microscopic observation of formulations with and without pumice were performed. Samples were also submitted to an accelerated stability study by centrifugation and to a thermal stress test. Through the testing, it was found that the amount of emulsifying agent affects the consistency and textural properties such as firmness and adhesiveness. So, formulations containing LSX (5% w/w) and decyl oleate or dimethicone as oily phase had a better consistency and remained stable with time, so exhibited the best features to be used for skin care products.Emulsões são a forma de apresentação mais comum dos produtos para aplicação na pele. No entanto estes sistemas podem exibir alguma instabilidade. Por esta razão, quando do desenvolvimento de emulsões para aplicação tópica é importante verificar se estas apresentam propriedades físicas ou mecânicas adequadas e avaliar a sua estabilidade. O objetivo deste trabalho consistiu no estudo da estabilidade de emulsões, cujas variações entre elas foi a proporção de agente emulsificante álcool estearílico (mais) laurilsulfato de sódio (mais) estearilsulfato de sódio (LSX), a natureza da fase oleosa (decil oleato, ciclometicona ou dimeticona) e a presença ou ausência de pedra-pomes (5% m/m). Mantendo as amostras à mesma temperatura, realizaram-se o estudo da reologia, a análise de textura e observação microscópica das formulações com e sem pedra-pomes. Amostras foram, também, submetidas a estudo de estabilidade acelerada por centrifugação e a ensaio de estresse térmico. Através dos testes realizados, constatou-se que a quantidade de agente emulsificante influencia a consistência e as propriedades de textura, como a firmeza e a adesividade. As formulações contendo LSX (5% m/m) e decil oleato ou dimeticona como fase oleosa exibiram melhores caraterísticas como produtos para aplicação na pele, uma vez que estas formulações apresentaram menor firmeza e consistência e permaneceram estáveis com o tempo

Main Benefits and Applicability of Plant Extracts in Skin Care Products

Natural ingredients have been used for centuries for skin care purposes. Nowadays, they are becoming more prevalent in formulations, due to consumers’ concerns about synthetic ingredients/chemical substances. The main benefits reported for plant extracts, used in skin care, include antioxidant and antimicrobial activities and tyrosinase inhibition effect. In this review, some examples of plants from Portuguese flora, whose extracts have shown good properties for skin care are presented. However, despite the known properties of plant extracts, few studies reported the development of formulations with them. More work in this field can be accomplished to meet consumer demand