Određivanje kadmija u vinu atomskom apsorpcijskom spektrometrijom

The objective of the present investigation was to develop a bilayer-floating tablet (BFT) for captopril using direct compression technology. HPMC, K-grade and effervescent mixture of citric acid and sodium bicarbonate formed the floating layer. The release layer contained captopril and various polymers such as HPMC-K15M, PVP-K30 and Carbopol 934p, alone or in combination with the drug. The floating behavior and in vitro dissolution studies were carried out in a USP 23 apparatus 2 in simulated gastric fluid (without enzyme, pH 1.2). Final formulation released approximately 95% drug in 24 h in vitro, while the floating lag time was 10 min and the tablet remained floatable throughout all studies. Final formulation followed the Higuchi release model and showed no significant change in physical appearance, drug content, floatability or in vitro dissolution pattern after storage at 45 oC/75% RH for three months. Placebo formulation containing barium sulphate in the release layer administered to human volunteers for in vivo X-ray studies showed that BFT had significantly increased the gastric residence time.Opisana je izravna metoda određivanja kadmija u uzorcima vina elektrotermičkom atomskom apsorpcijskom spektrometrijom (ETAAS). Za atomizaciju su upotrebljene pirolitičke grafitne cjevčice i grafitne cjevčice sa standardnom pirolitičkom platformom po L’vovu. Granica određivanja bila je 0,08 microg L1 kadmija. Relativna standardna devijacija za koncentracijsko područje od 0,2 do 10 g L-1 bila je između 1 i 7%. Točnost metode potvrđena je usporedbom rezultata s rezultatima dobivenih iz vlažno digeriranih uzoraka i spiked uzoraka. Pomoću ove metode određeno je da se koncentracija kadmija u makedonskim vinima kreće u rasponu od 0,10 do 0,90 microg L-1

In Vitro Evaluation of a Stable Monomeric Gold(II) Complex with Hematoporphyrin IX: Cytotoxicity against Tumor and Kidney Cells, Cellular Accumulation, and Induction of Apoptosis

The antineoplastic potential of a stable monomeric Au(II) complex with hematoporphyrin IX (Hp), namely [Au(II)Hp−2H.(H2O)2], was investigated in a panel of tumor cell lines. The complex exhibits strong cytotoxicity, whereby the leukaemia- and lymphoma-derived cell lines are more sensitive, with IC50 values comparable to those of the reference anticancer drug cisplatin. In contrast, the solid tumor models are more sensitive to the platinum drug. A comparative assessment of both agents against the human kidney cell line 293T has shown that [Au(II)Hp−2H.(H2O)2] is less cytotoxic. The gold complex induces oligonucleosomal DNA fragmentation in tumour cells following 24-hour treatment and hence its cytotoxic effect is at least partly mediated by induction of apoptotic cell death. A prominent intracellular gold accumulation was detected after treating tumor cells with [Au(II)Hp−2H.(H2O)2] which shows that its putative pharmacological targets are readily accessible after a short incubation period

Preconcentration Methods for Determination of Thallium in Natural Waters

Two preconcentration procedures for electrothermal atomic absorption (ETAAS) determination of thallium in mineral, spring, tap, river, underground and sea water were developed and compared: (i) Column solid phase extraction with new sandwich type disposable sorbent columns

Arsenic, cadmium and lead in medicinal herbs and their fractionation

Arsenic, cadmium and lead were determined for quality control monitoring purposes of Bulgarian herbs and their infusions by inductively Coupled plasma mass spectrometry and electrothermal atomic absorption spectrometry. Twelve samples of yarrow (Achillea millefolium), 18 of chamomile (Flores Chamomillae), 8 of bearberry leaves (Folia uvae ursi), 24 of peppermint (Mentha piperitoe folium), 10 of hibiscus (Hibiscus sabdariffa), 14 of oregano (Origanum vulgare) and 12 of thyme (Thymus serpyllum) were analyzed. The studied toxic elements were present in the medicinal plants (12-225 mu g/kg As, 15-268 mu g/kg Cd, 0.2-8.6 mg/kg Pb). Arsenic was found in all herbal infusions at levels up to 0.4 mu g/l. Cadmium was present in infusion!; of chamomile, hibiscus, peppermint and thyme at levels Lip to 0.7 mu g/l. Lead was detected only in hibiscus infusions (2-3 mu g/l). It was established that the major part of arsenic and lead in herbal infusions existed in biomacromolecular fraction. Cadmium appears to be present mainly in cationic form at pH 1 (stomach acidity), but at pH 7.6 (intestine acidity) there is a non-cationic fraction as well

Preconcentration Methods for Determination of Thallium in Natural Waters

Two preconcentration procedures for electrothermal atomic absorption (ETAAS) determination of thallium in mineral, spring, tap, river, underground and sea water were developed and compared: (i) Column solid phase extraction with new sandwich type disposable sorbent columns

In vitro assessment of manganese bioavailability from Hibiscus sabdariffa (Karkade) tea

Karkade tea may be a rich dietary source of Mn, since the dried hibiscus calyces contain 300-950 mg/kg of this essential element. The soluble elemental content was between 55% and 85% in dependence on the plant origin and on the tea preparation procedure (temperature, leaching duration). The potential bioavailability of dissolved Mn was studied using chemical fractionation including ion exchange, liquid phase extraction and selective precipitation. Flame atomic absorption spectrometry was applied for element determination in all fractions. The main part of Mn (>90%) presents in fresh prepared tea as positively charged species with low molecular weight (free cation or labile complexes) considered as potentially bioassimilable. In vitro assessment of manganese bioaccessibility was performed using sequential enzymatic simulation of gastro-intestinal digestion in combination with operational fractionation. Under simulated intestinal conditions the bioaccessible fraction of Mn was approximative 40% from its total content. Daily drinking of 200 ml karkade tea will contribute around 9 % of RDA/RDI of this element in a potentially bioaccessible form.The bioavailability of Mn from hibiscus infusions was compared with that of other major and trace essential elements. The percentages of low molecular weight and potentially more bioabsorbable forms of elements following simulated gastro-intestinal digestion were around 35% (Ca), 83% (Cu), 44% (Fe), 55% (Mg), 90% (K), 85% (Zn) from their total dissolved content