RESUMO
Together with vitamin C, zinc, selenium, manganese, and magnesium play a vital role in the preservation of organs scheduled for transplantation. In the present study, it is shown that addition of 1 mg/l of these elements influences the stability of 0.3 mM ascorbic acid solutions. The solution's stability was estimated using an accelerated stability test. The concentration of vitamin C was measured using a validated spectrophotometric method, which uses the reduction of 2,6-dichlorophenoloindophenol by ascorbic acid. Elevated temperatures, the factor accelerating substances' decomposition reaction rate, were used in the tests. The research was conducted at two temperatures at intervals of 10 °C: 80 ± 0.1 and 90 ± 0.1 °C. It was stated that the studied substances' decomposition occurred in accordance with the equation for first-order reactions. The function of the logarithmic concentration (log%C) over time was revealed to be rectilinear. This dependence was used to determine the kinetics of decomposition reaction rate parameters. The stabilization of vitamin C solutions was measured as the time in which 10 % of the substance decomposed at 20 and 0 °C. Addition of Se(IV) or Mg(II) ions significantly increase the stability of ascorbic acid solution (â¼34 and â¼16 %, respectively), but Zn(II) causes a significant decrease in stability by â¼23 %. Addition of Mn(II) has no significant influence on vitamin C stability.
Assuntos
Antioxidantes/química , Ácido Ascórbico/química , Magnésio/química , Selênio/química , Oligoelementos/química , Antioxidantes/análise , Ácido Ascórbico/análise , Estabilidade de Medicamentos , Fumaratos/química , Temperatura Alta , Cinética , Manganês/química , Compostos de Manganês/química , Soluções para Preservação de Órgãos/química , Concentração Osmolar , Oxirredução , Conservantes Farmacêuticos/química , Selenito de Sódio/química , Sulfatos/química , Zinco/química , Acetato de Zinco/químicaRESUMO
The effect of egg yolk phosvitin on the permeation and absorption of calcium was investigated in vitro in relation to calcium gluconate concentration. Obtained results indicate that phosvitin significantly reduces the intestinal calcium absorption from 1 and 10 mM of calcium gluconate solution. It is associated with the formation of the complex of Ca (II) ions with phosvitin. The process of calcium permeation increases under phosvitin influence when calcium gluconate concentrations rise up to 10 mM. At a higher concentration of calcium gluconate (20 mM), no effect of phosvitin was seen on permeation of calcium ions.
Assuntos
Gluconato de Cálcio/farmacologia , Cálcio/farmacocinética , Absorção Intestinal/efeitos dos fármacos , Fosvitina/farmacologia , Animais , Relação Dose-Resposta a Droga , Técnicas In Vitro , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/metabolismo , Íons/farmacocinética , Permeabilidade/efeitos dos fármacos , SuínosRESUMO
The prolactin (PRL) permeation through the pericardium depending on the species of origin (porcine, bovine and ovine) was studied, and the parameters of its bioavailability were calculated. An in vitro model using pericardium as a natural membrane and Frantz cell method was applied. Significant differences in permeation were observed depending on the species of origin. Within 5 h, 17.5% of bovine PRL, 27.2% of porcine PRL and 90.3% of ovine PRL permeated the pericardium. The amount of permeated ovine PRL was 3.3-fold higher than porcine PRL and 5.2-fold higher than bovine PRL. The maximum concentration of permeated PRL was reached in the thirtieth minute of the experiment and was the highest for ovine PRL (C(max) = 677.21 µg/cm²) and the lowest for bovine PRL (C(max) = 259.97 µg/cm²). Bioavailability of PRL through the pericardium is 3.3-fold greater for ovine PRL in comparison to porcine or bovine PRL. The relative extent of bioavailability for bovine and ovine prolactin versus the porcine PRL standard was 85.6% and 229.3%, respectively.
