Assessment of liquid disposal originated by uranium enrichment at Aramar Experimental Center São Paulo--Brazil.

This work presents a liquid disposal monitoring originated from uranium enrichment process at Aramar Experimental Center from 1990 to 1998. Assessment of uranium, fluorides, ammoniacal nitrogen, chemical oxygen demand, and pH measurements were made in water samples and compared with results achieved in other countries, as North America and India. The liquid disposal evaluation, generated by uranium enrichment process, showed low levels, considering most parameters established by Federal and State Legislation, aiming environmental pollution control. However, uranium levels were above the limits established by Conselho Nacional do Meio Ambiente, Environment Protection Agency and mainly by the World Health Organization.

Development and evaluation of a floating multiparticulate gastroretentive system for modified release of AZT.

The aim of this study was to develop and evaluate a floating multiparticulate gastroretentive system for the modified release of zidovudine (AZT). AZT was used as a model drug water-soluble at therapeutic doses. The floating gastroretentive system was obtained by co-precipitation, after solvent diffusion and evaporation. The proposed system was evaluated in vitro for particle morphology, lag time and floating time, loading rate, release profile, and the release kinetic of AZT release. AZT's physico-chemical characteristics were evaluated by differential scanning calorimetry (DSC), X-ray diffraction (XDR) and infrared spectroscopy (IR). The particles obtained were sphere-shaped, hollow, and had porous walls. The floating was immediate, and floating time was higher than 12 h. The loading rate was 34.0 ± 9.0%. The system obtained had an extended release. DSC and XDR results showed a modification in AZT's solid state. IR spectroscopy revealed that the chemical structure of the AZT was unchanged. The hollow microballoons presented gastroretentive, floating, and extended-release properties.

In vitro evaluation of copaiba oil as a kojic acid skin enhancer

The capacity of copaíba oil to act as a skin penetration enhancer for the depigmenting agent kojic acid was evaluated using an in vitro diffusion system with static flux and shed rattlesnake skin membrane, Crotalus durissus terrificus, in saline solution at 34±2 ºC as the fluid receptor. The quantities of kojic acid liberated into the fluid receptor were determined by spectrophotometry at 268 nm with intervals of one and a half hours. The membranes, pretreated with copaíba oil at 25 percent and 50 percent v/v, gave flux values of 8.0 and 12.7 µg/cm²/h, permeability values of 2.0 and 3.3 cm×10-4/h, and promotion factors of 4.1 and 3.7, respectively. These results indicate that copaíba oil, at the two concentrations studied, has the capacity to promote penetration of kojic acid.

A propriedade do óleo de copaíba como agente promotor de penetração cutânea do despigmentante ácido kójico foi avaliada utilizando-se sistema de difusão in vitro com fluxo estático, membrana de pele da serpente cascavel - Crotalus durissus terrificus e solução salina a 34±2 ºC como fluido receptor. As quantidades liberadas do ácido kójico no fluido receptor foram determinadas por espectrofotometria em 268 nm em intervalos de 1:30 h. As membranas pré-tratadas com óleo de copaíba a 25 e 50 por cento v/v apresentaram valores de fluxo de 8,0 e 12,7 µg/cm²/h, permeabilidade de 2,0 e 3,3 cm×10-4/h, e fatores de promoção de 4,1 e 3,7, respectivamente. Os resultados obtidos indicaram que o óleo de copaíba, nas duas concentrações estudadas, apresentou capacidade de promoção da penetração do ácido kójico.