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The electrochemical behavior of the echinocandin antifungals anidulafungin (AF) and micafungin (MF) has been investigated by differential pulse polarography (DPP). The measurements were carried out in a supporting electrolyte solution consisting of Britton-Robinson buffer and methanol at various substance concentrations and pH values. An amperometric cell with a three electrode system consisting of a dropping mercury electrode (DME) as working electrode, an auxiliary platinum electrode and an Ag/AgCl reference electrode was used in all experiments. AF was electrochemically reduced at potentials between -1.3 and -1.5 V. MF showed a first reduction peak (a) between -1.0 and -1.4 V and a second peak (b) between -1.5 and -1.8 V. A strong pH-dependence was observed, with optimal results at pH 2.0-3.0 for the AF peak, pH 2.0 for the MF peak (a) and pH 5.0 for the MF peak (b). A linear correlation between the concentration and the peak current has been demonstrated for all reduction peaks. MF peak (a) showed a similar behavior to the AF peak regarding shape, peak current and pH-dependence. Therefore, it can be assumed that both reductions are based on the same mechanism, a two-step reduction of the N-acyl group.

Medicininal compounds and their metabolites are known to end up in sewerage and may slip through the cleaning process. Azole antimycotics are frequently used in hospitals, in particular for patients with cancer or immunosuppression. The aim of the study was to determine whether measurable azole antimycotic concentrations were introducted in the sewarage drain of an acute care hospital with special interest in oncology and hematology and the extent of removal of antimycotics by the sewerage treatment plant. For this, the concentrations of three commonly used azole antimycotics were measured in the effluent of the sewerage drain at the University Hospital Dresden, as well as in the influent and effluent of the main sewerage treatment plant of the city. To extrapolate the theoretical influent to the sewerage treatment plant, prescription from the regio`s main health insurance the AOK Sachsen and the hospital consumption data were used. Measurable concentrations were obtained for fluconazole and ketoconazole in the influent and effluent of the sewerage treatment plant. Voriconazole's concentrations were under the lower limit of quantification. To determine the azole clearance of the treatment plant a sludge sample was investigated. Sufficient clearance was detected for ketoconazole but not for fluconazole. The consumption and prescription rates were collected and correlated with the measured concentrations. In result, only fluconazole's concentrations provided a good match with the prescription and consumption data.

Detection of Candida mannan and Aspergillus galactomannan in serum with the Platelia enzyme immunoassay is applied for diagnosing invasive fungal infections. High risk patients for invasive fungal infections are often receiving parenteral nutrition. It is important to know whether false-positive Platelia test results occur during total parenteral nutrition. Studies to false-positivity in intravenous feeding solutions lack so that we start an in-vitro investigation. We used two different enzyme immunoassays to test the feeding solutions. We tested infusions (n = 19) which are applied for the production of individual parenteral nutrition in the University Hospital Carl Gustav Carus Dresden. We used the Platelia Aspergillus EIA to analyse the Aspergillus antigen galactomannan in the solutions. In addition, the Platelia Candida Ag plus was used to determine the concentration of the Candida antigen mannan. In summary, four solutions (21%) showed measurable concentrations of the Candida mannan. They were considered positive with a concentration > 0.125 ng/ ml mannan (Tracitrans infant, calcium gluconate solution) and borderline with a concentration between 0.0625 and 0.125 ng/ml mannan (Tracitrans plus, SMOFlipid). None of the analysed infusions contained the Aspergillus galactomannan. In conclusion, further investigations on the topic are necessary to determine their in-vivo impact. A positive Platelia test result can simulate the presence of invasive fungal infections. As a consequence the patient may be treated with expensive, systemic antimycotics with a high risk of adverse events. Therefore a definite diagnosis is important.

The electrochemical behavior of the azole antifungal agents itraconazole, posaconazole and ketoconazole has been investigated at a glassy carbon working electrode using cyclic voltammetry. All measurements were carried out in a supporting electrolyte solution consisting of a 1:1 (v/v) mixture of 0.1 mol L(-1) sodium phosphate buffers and acetonitrile at various substance concentrations and pH values. An amperometric cell with a three electrode system consisting of a working electrode, a palladium reference electrode and a platinum disk as the auxiliary electrode was used in all experiments. All azoles showed a similar electrochemical behavior involving two reactions. An irreversible oxidation occurred at potentials of about 0.5V. A reduction peak was detected at potentials between -0.28V and -0.14V with an associated oxidation peak, which was observed in consecutive repeated measurements at potentials between -0.03 and 0.28 V. The reduction and corresponding oxidation can be regarded as a quasi-reversible process. The proposed reaction mechanisms are an irreversible oxidation of the piperazine moiety at higher potentials as well as a reduction at lower potentials of the carbonyl group of the triazolone moiety in the case of itraconazole and posaconazole or a reduction of the methoxy group of ketoconazole.

The electrochemical reactions of the antifungal drugs itraconazole, ketoconazole, fluconazole and voriconazole have been investigated by differential pulse polarography (DPP) using a dropping mercury electrode (DME). All investigations were carried out in Britton-Robinson buffer solutions and methanol with varying pH values. Ketoconazole and itraconazole both showed a reduction peak with a potential between -1.5V and -1.6 V. Stable and reproducible conditions for the determination of itraconazole (c = 1 x 10(-7) M) were found within the pH range of 6.0 to 8.0 and for the determination of ketoconazole (c = 5 x 10(-8) M) within pH 6.0 to 7.0. Voriconazole showed a reduction peak with a peak potential of -1.7 V (c = 1 x 10(-5) M) within the pH range of 8.0 to 10.0. In the case of fluconazole no electrochemical activity was found.

The electrochemical reduction of the proton pump inhibitors (PPI) lansoprazole and rabeprazole has been investigated by differential pulse polarography (DPP) using a dropping mercury electrode (DME). The results were compared not only among both substances but also among other proton pump inhibitors depending on the varying chemical structures of the agents. All investigations were carried out in Britton-Robinson buffer solutions with pH values from 3.0 to 11.0. It was shown that both PPI undergo an extensive decomposition decreasing with increasing pH values forming two main compounds, a cyclic sulfenamide and a dimer. In this case lansoprazole was found to be stable at pH 8.0 and rabeprazole at pH 9.0. The decomposition of rabeprazole ran considerably quicker and also up to higher pH values than those of lansoprazole. The peak currents varied linearly with the concentration of both PPI in the range from 1 x 10(-6) M to 7 x 10(-5) M at pH 9.0. Both substances showed similarities in reaction as well as individual differences based on their varying chemical structures and characteristics.

The electrochemical behaviour of the proton pump inhibitor pantoprazole was analysed. The similarity of the DPP- and DC(T)-curves including all important characteristics suggest that the postulated mechanism of the electrochemical reduction of omeprazole is transferable to pantoprazole.