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A presença de cinco plastificantes derivados de ftalatos em equipamentos para administração intravenosa de soluções e em hemodialisadores (HD), que são feitos tanto de policloreto de vinila (PVC) quanto de outros materiais poliméricos, foi investigada. Destes ftalatos, o único autorizado por agências reguladoras é o di-(2-etilhexil) ftalato (DEHP) em equipamentos de PVC. A determinação foi feita por chromatografia líquida de alta eficiência (HPLC) com detecção UV. Os resultados mostraram que as bolsas para infusão que são feitas tanto de PVC quanto de etil vinil acetato (EVA) contêm apenas DEHP. Entretanto, as mangueiras dos equipos de infusão e dos HD, bem como as fibras capilares dos HD feitas de celulose, contêm não só DEHP, mas também ftalato de dibutila (DBP). Todos os cinco ftalatos investigados foram encontrados nos capilares dos HD feitos de polisulfona. A migração de DEHP para soluções (aminoácidos, glicose e salina) armazenadas em bolsas ocorreu com taxas diferentes para os dois polímeros. Enquanto que para as bolsas de PVC o DEHP foi encontrado em soluções já nos primeiros dias de contato, para as bolsas de EVA a migração iniciou após aproximadamente 6 meses de armazenamento. Como os dispositivos analisados, com exceção das bolsas, contém, além do DHEP, outros ftalatos, o risco posto aos pacientes deve ser motivo de preocupação.The presence of five plasticizer phthalates in bags and sets for intravenous administration and hemodialyzers (HD), which are made of polyvinyl chloride (PVC) and of other polymeric materials, was investigated. Di-(2-ethylhexyl) phthalate (DEHP) in PVC is the only authorized phthalate by regulatory agencies. Phthalate determination was carried out by high resolution liquid chromatograph (HPLC) with UV detection. The results showed that the infusion bags that are made of both PVC and ethylene vinyl acetate (EVA) contained only DEHP. In contrast, the tubing of infusion sets and of HD (as well as the cellulose capillaries of HD) contained not only DEHP but also dibutyl phthalate (DBP). Moreover, all five investigated phthalates were found in HD polysulfone capillaries. Migration of DEHP into the stored solutions (amino acids, glucose and saline) in bags occurred at different rates from one polymer to another. While DEHP from PVC bags was found in solutions within the first days of contact, the migration from EVA bags started only after approximately 6 months of solution storage. Since PVC and non-PVC devices (as well as capillaries of HD sets) contain DEHP and other phthalate-based plasticizers, the extent of the risk that they pose to patients remains a matter of concern.

Aluminum (Al) is the most widely distributed metal in the environment and is extensively used in daily life leading to easy exposure to human beings. Besides not having a recognized physiological role, Al may produce adverse effects through the interaction with the cholinergic system contributing to oxidative stress. The present study evaluated, in similar conditions of parenteral nutrition, whether the reaction of silicon (SiO2) with Al(3+) to form hydroxyaluminosilicates (HAS) reduces its bioavailability and toxicity through intraperitoneal administrations of 0.5 mg Al/kg/day and/or 2 mg Si/kg/day in Wistar rats. Al and Si concentrations were determined in rat brain tissue and serum. Acetylcholinesterase (AChE) activity and lipid peroxidation (LPO) were analyzed in the cerebellum, cortex, hippocampus, striatum, hypothalamus, and blood. An increase in the Al concentration was verified in the Al + Si group in the brain. All the groups demonstrated enhanced Si compared to the control animals. Al(3+) increased LPO measured by thiobarbituric acid reactive substances (TBARS) in cerebellum and hippocampus, whereas SiO2 reduced it when compared with the control group. An increase of AChE activity was observed in the Al-treated group in the cerebellum whereas a decrease of this enzyme activity was observed in the cortex and hippocampus in the Al and Al + Si groups. Al and Si concentrations increased in rat serum; however, no effect was observed in blood TBARS levels and AChE activity. SiO2 showed a protective effect in the hippocampus and cerebellum against cellular damage caused by Al(3+)-induced lipid peroxidation. Thus, SiO2 may be considered an important protector in LPO induced by Al(3+).

Studies suggest that silicic acid or silica can reduce the oral absorption and increase the excretion of aluminum thus protecting the organism against the adverse effects induced by this metal. Therefore, the simultaneous or concomitant determination of Al and Si in biological samples is of significance. In this study a method for sample treatment and the determination of both Al and Si by graphite furnace atomic absorption spectrometry (GFAAS) in animal tissue was developed. Sample dissolution with tetramethylammonium hydroxide (TMAH) proved to be suitable for the determination of both elements.Because Si enhances the Al signal during atomization, this element acted as a chemical modifier for the determination of Al. For the determination of Si, palladium nitrate was the most suitable modifier. The use of Zr as a permanent modifier minimized the tube degradation caused by TMAH. The limits of detection were 5.8 mg L À1 for Al and 29.0 mg L À1 for Si, and the recoveries in spiked samples were between 97 and 112%. The method was validated against bovine liver standard reference materials (SRM 1577b and 1577c), and the obtained concentrations agreed with the certified values.

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