RESUMO
The aim of this work was to determine the toxicity of ethanol in an aquatic system by means of bioassays with Oreochromis mossambicus (Peters) as a test organism. The study revealed changes in the gill ATPase activities. The results obtained indicated that ethanol brought about a decrease in the body weight, followed by significant inhibition on total ATPase, Na(+)/K(+) ATPase, Ca(2+) ATPase and Mg(2+) ATPase activities. The studies also indicated that these can be employed as suitable biomarkers in ethanol related toxicity studies.
RESUMO
The microspheres of crosslinked starch have been prepared and characterized by IR spectral analysis and SEM technique. The prepared microspheres were loaded with an anticoagulant drug 'heparin' and the kinetics of in-vitro release of heparin was investigated spectrophotometrically at physiological pH (7.4) and body temperature (37 degrees C). The influence of percent loading of heparin, chemical architecture of the microspheres and pH of the release medium were examined on the release profiles of the drug. The chemical stability of heparin was tested in phosphate buffer saline (pH 7.4) and the release was also studied in various simulated biological fluids.
Assuntos
Líquidos Corporais/química , Cápsulas/química , Preparações de Ação Retardada/química , Portadores de Fármacos/química , Heparina/administração & dosagem , Heparina/química , Amido/química , Reagentes de Ligações Cruzadas/química , Preparações de Ação Retardada/administração & dosagem , Difusão , Portadores de Fármacos/administração & dosagem , Composição de Medicamentos/métodos , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , CinéticaRESUMO
A hydrophilic semi-interpenetrating polymer network of polyvinyl alcohol (PVA), poly(ethylene glycol) (PEG) and crosslinked polyacrylamide (PAM) chains has been synthesized and its potential for controlled release of macromolecular drugs has been assessed by taking insulin as a representative drug. The semi-IPN was characterized by IR studies and network parameters such as the average molecular weight between crosslinks (Mc), crosslink density (q), and number of elastically effective chains (Ve) were evaluated. The effect of chemical architecture of the IPN was investigated on the percent loading of insulin and its subsequent release from the loaded device. Other parameters such as the thickness of the gel, molecular weight of PEG and pH and temperature of the release medium were also studied for their possible impact on the release of insulin. The whole release data was analyzed by Ficks power law and the influence of various factors on the plausible mechanism of insulin release was investigated.
