Determination of free cisplatin in medium by differential pulse polarography after ultrasound and cisplatin treatment of a cancer cell culture.

The in vitro study was carried out for detection of the cisplatin in free form and in culture medium, depending on various conditions of sonodynamic human ovarian cancer cells A2780 treatment by differential pulse polarography (DPP). For sonodynamic treatment, we used cisplatin alone and combined cisplatin/ultrasound treatments. The ultrasound exposure intensity of 1.0 and 2.0 W∙cm-2 in far field for incubation periods 1, 24 and 48 h was used. The parameters of DPP measurements were - 1 s drop time, 5 mV.s-1 voltage scan rate, 50 mV modulation amplitude and negative scanning direction; platinum wire served as counter electrode and Ag|AgCl|3 M KCl as reference electrode. The results showed the dependence of free platinum quantities in culture medium on incubation time and treatment protocol. We found difference in concentration of free cisplatin between conventional application of cisplatin and sonodynamic treatment. The sonodynamic combined treatment of cisplatin and ultrasound field showed a higher cisplatin content in the culture medium than cisplatin treatment alone; a difference of 20% was observed for incubation time 48 h. The results also showed the influence of a time sequence of ultrasound and cytostatics in the sonodynamic treatment. The highest amount of free cisplatin in the solution was found for primary application of cisplatin and the subsequent ultrasound exposure. The quantity of free cisplatin increased with time, namely for time intervals 1-24 h. There was no difference between the DPP signal of cisplatin in reaction mixture containing cells in small quantities and micro-filtered mixture without cells. Thus, the DPP method is suitable for the detection and quantification of free cisplatin in the culture medium of cell suspension. Ultrasound field can be important factor during cytostatic therapy.

Electroreduction of some naphthylazo compounds using polarography and cyclic voltammetry techniques

The polarographic and cyclic voltammetric reduction of alpha-, beta- and 4-sulphonaphthylazochromotropic acid dyes were studied in aqueous B.R. buffer solutions of pH = 2-12. Over the entire pH range, alpha- and beta-naphthylazo compounds were reduced through an irreversible diffusion-controlled 2-electron wave representing the saturation of the N = N center to the hydrazo stage. For 4-sulpho compound an irreversible diffusion-controlled 4-electron wave was obtained corresponding to complete reduction of its azocenter to the amino stage. The voltammograms of alpha-and-beta-naphthylazo compounds in solution of different pH's exhibit a single cathodic peak, whereas 2 cathodic peaks are observed for 4-sulpho compound. The mechanistic pathway of the electrode reaction was suggested and the kinetic parameters were calculated and discussed

Empleo de la polarografía de pulso diferencial en el análisis de impurezas metálicas en muestras farmacéuticas: III / Use of differential pulse polarography in the analysis of metallic impurities in pharmaceutical samples: III

Se desarrollan procedimientos generales aplicables para la determinación simultánea de impurezas de cobre, plomo, cadmio y cinc en muestras farmacéuticas que incluyen materias primas insolubles, tabletas de ácido acetilsalicílico y similares, y materiales plásticos de uso en farmacia, con el empleo de la polarografía de pulso diferencial. La posibilidad que ofrece este método de detectar y cuantificar de forma individual esos iones en una sola determinación, a lo que se le unen otras ventajas como son rapidez y bajo costo, lo presenta como una alternativa importante del análisis global y semicuantitativo por precipitación de sulfuros, que tradicionalmente se ha prescrito como prueba oficial por las diferentes farmacopeas