Development, characterization and evaluation of the dissolution profile of sulfasalazine suspensions

This paper reports the development, characterization and in vitrodissolution behavior of sulfasalazine suspensions for treatment of chronic intestinal inflammatory diseases. Three formulations were developed, from powdered sulfasalazine obtained from different suppliers. The sulfasalazine was characterized regarding concentration, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), particle size distribution, polydispersion and solubility. The suspensions were developed and characterized regarding pH, viscosity, density, particle size, sedimentation volume, concentration and dissolution. The pH values were slightly acidic. The method of preparing the suspensions reduced the particle sizes and made the size distribution more homogeneous. The dissolution studies showed that the sulfasalazine suspensions had low solubility in acidic media, but dissolve quickly, reaching levels of 85%, in neutral media or media containing 0.5% of surfactants such as polysorbate 80. Besides this, the sulfasalazine suspensions were classified as having immediate dissolution because they reached dissolution levels near 100% in 20 minutes.</p

Exigências nutricionais e crescimento de plantas de mogno (Swietenia macrophylla King.) Nutritional requirements and growth of mahogany (Swietenia macrophylla King.) plants

A necessidade de desenvolver pesquisas referentes aos requerimentos nutricionais das espécies florestais, principalmente as essências florestais nativas da Amazônia, como o mogno, é inadiável, visto que as constantes explorações de espécies de alto valor econômico são cada vez maiores. Com o objetivo de avaliar o crescimento e o requerimento nutricional de mudas de mogno, foi realizado um experimento em casa de vegetação com 14 tratamentos. O delineamento experimental foi de blocos casualisados, com 5 repetições. As características de crescimento avaliadas foram: altura da parte aérea, diâmetro de colo, matéria seca da parte aérea, da raiz e total, relação raiz e parte aérea e conteúdo de nutrientes da matéria seca da parte aérea. Os resultados obtidos permitem concluir que: é necessária a correção conjunta da acidez e da fertilidade do solo para solos ácidos e de baixa fertilidade natural, mesmo que o teor de matéria orgânica seja considerado alto; dos nutrientes, P é o que mais limita o desenvolvimento da planta, bem como a absorção dos outros nutrientes; não há necessidade de adição de K para o desenvolvimento das plantas quando se realiza calagem; na ausência de calagem a adição de K deve ser recomendada e o requerimento nutricional do mogno em macronutrientes obedece à ordem decrescente de: P>S>K>N.<br>The need for developing research related principally to the nutritional requirements of essential native Amazonian forest species, such as mahogany, is urgent, since the exploration of highly valuable species is continually more frequent. With the objective of evaluating the growth and the nutritional requirement of mahogany plants, an experiment in a vegetation house with 14 treatments was undertaken. The experiment outline was of occasional blocks with 5 repetitions. The growth characteristics evaluated were: height of the aerial part, diameter of the bottom, dry material of the aerial part, root and total, relationship of root and aerial part, relationship and nutrient content of dry material of the aerial part. The results lead to the conclusion that: the conjoint correction of acidity and the fertility of the soil for acid soils and low natural fertility is necessary even if the content of the organic material is considered high; of the nutrients, P is the one which limits most the development of the plant, as well as the absorption of other nutrients; there is no need to add K for developing the plants when liming occurs.; addition of K is recommended when liming does not occur; and the nutritional requirement of mahogany in macronutrients obeys the decreasing order of P>S>K.N