No abstract

No abstract

Some atomic spectrometric determinations of metals in aliphatic polyester and polycarbonate biomedical polymers Summary-Contents of Al, Zn, Sn and Cr have been investigated in several aliphatic polyesters and polycarbonates obtained in ring opening polymerization and copolymerization of heterocyclic monomers in the presence of coordination catalytic systems with these metals. The metals were reliably determined using spectroscopic atomic techniques: flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). Commercial materials like NatureWorks® polylactide, poly(propylene carbonate) and medical sutures (e.g. Dexon®, Vicryl®) were also tested. The results are discussed in terms of applicable catalytic systems for the syntheses of biodegradable polymers, which are sufficient to reach metal concentrations specified in European Pharmacopoeia.

Oznaczanie pozosta³ooeci cyny w syntetyzowanych biomedycznych poliestrach alifatycznych metod¹ elektrotermicznej absorpcyjnej spektrometrii atomowej Streszczenie-Metod¹ polimeryzacji z otwarciem pieroecienia, katalizowanej 2-etyloheksanianem cyny (SnOct 2) otrzymano cykliczne poliestry: polilaktyd (PLA) i poli(e-kaprolakton) (PCL). Uzyskane produkty poddawano procesowi kilkakrotnego oczyszczania z pozosta³ooeci cynoorganicznego katalizatora. Zawartooeae Sn w polimerach, po ka¿dym kolejnym oczyszczaniu, oznaczano za pomoc¹ elektrotermicznej absorpcyjnej spektrometrii atomowej (ET-AAS). Wyniki analiz dyskutowano uwzglêdniaj¹c wymagania Farmakopei Europejskiej dotycz¹ce dopuszczalnej zawartooeci cyny w biomedycznych poliestrach alifatycznych. Stwierdzono, ¿e czterokrotne oczyszczanie produktu polireakcji pozwala na obni¿enie poziomu stê¿enia Sn o 3 rzêdy wielkooeci, do wartooeci mniejszych ni¿ okreoelone przez Farmakopeê dla materia³ów maj¹cych kontakt z krwi¹, ponadto operacje te nie powoduj¹ degradacji polimeru. S³owa kluczowe: poliestry alifatyczne, polilaktyd, poli(e-kaprolakton), polimery biomedyczne, elektrotermiczna absorpcyjna spektrometria atomowa. DETERMINATION OF RESIDUAL TIN IN SYNTHESIZED ALIPHATIC BIOMEDICAL POLY-ESTERS BY ELECTROTHERMAL ATOMIC ABSORPTION SPECTROSCOPY Summary-The synthesis of the aliphatic polyesters-polylactide (PLA) and poly (e-caprolactanes) (PCL) in the ring-opening polymerization of cyclic esters in the presence tin(II) 2-ethylhexanoate (SnOct 2) has been presented. The obtained products were subjected to multiple purification procedures to remove residual organo-tin catalyst (Tables 2 and 3). The tin content in the polyesters was then determined by Electrothermal Atomic Absorption Spectroscopy (ET-AAS) (Tables 3 and 4) after each purification process. The results of the analysis were discussed taking into consideration the requirements placed by the European Pharmacopoeia regarding the amount of tin allowed in aliphatic biomedical polyesters. It was confirmed, that a four-stage purification of the polyreaction product led to a threefold decrease in the concentration of tin to a level less than the value required by Pharmacopoeia for materials designated for contact with blood. Moreover, the purification process did not generate any degradation of the polymer.

Alzheimer disease is a neurodegenerative process of unknown mechanism taking place in a part of the brainhippocampus. Oxidative stress and the role of iron in it is one of the suggested mechanisms of cells death. In this study several methods were used to assess iron and iron binding compounds in human hippocampus tissues. Mössbauer spectroscopy was used for identification of the iron binding compound and determination of total iron concentration in 12 control and one Alzheimer disease sample of hippocampus. Mössbauer parameters obtained for all samples suggest that most of the iron is ferritin-like iron. The average concentration of iron determined by Mössbauer spectroscopy in control hippocampus was 45 ± 10 ng/mg wet tissue. The average concentration of iron in 10 Alzheimer disease samples determined by atomic absorption was 66 ± 13 ng/mg wet tissue. The concentration of H and L chains of ferritin in 20 control and 10 AD hippocampi was assessed with enzyme-linked immuno-absorbent assay. The concentration of H and L ferritin was higher in Alzheimer disease compared to control (19.36 ± 1.51 vs. 5.84 ± 0.55 ng/µg protein for H, and 1.39 ± 0.25 vs. 0.55 ± 0.10 for L). This 3-fold increase of the concentration of ferritin is accompanied by a small increase of the total iron concentration.