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The aim of this study was to determine the transportations of rivastigmine containing from various liposome formulations through Madin Darby Canine Kidney (MDCK) cells monolayer and to compare the in vitro test results with in vivo. There is no other liposome formulation of rivastigmine and the transportations of rivastigmine through MDCK cell monolayers or related study available in the literature. Cytotoxicity (MTT) test was used to determine cell viabilities. The effect of sodium-taurocholate or dimethyl-beta-cyclodextrine as penetration enhancer was also investigated. Characterization and stability studies for liposome formulations were performed. Permeation experiments of rivastigmine were performed through MDCK cells and dialysis membrane. The kinetic of release from liposomes was also investigated. The highest apparent permeability coefficient (log. values) was obtained with sodium-taurocholate liposomes for -1.15 ± 0.16 for MDCK cell. Rivastigmine liposomes and solutions were also administered to mice orally and intraperitonally. Acetylcholinesterase (AChE) activity was determined by Ellman method. AChE% inhibition values were calculated for both blood and brain after administration of rivastigmine solution and liposomes. The highest AChE inhibition was observed for rivastigmine-sodium-taurocholate liposomes. Histological observations of the mice' brains were performed under transmission electron microscope (TEM). The histological results were also indicated and supported all these findings.

Ninety female Balb/c mice were used. The animals were allocated to evenly six groups. While the first group was maintained as control, Groups 3, 4, 5, and 6 were administered 750 ppm, 1500 ppm, 3000 ppm, and 6000 ppm of N-acetylcysteine, respectively, for a period of 15 days. After day 15, Groups 2-6 were administered sodium fluoride, containing 100 ppm fluoride in drinking water, for another 15 days. Plasma malondialdehyde (MDA) levels and erythrocyte superoksid dismutase (SOD) and catalase (CAT) activities were determined at the beginning of the trial and on days 15 and 30. According to the data obtained in the present study, N-acetylcysteine, when administered at the indicated doses, did not produce a significant alteration in any of the three parameters investigated. On the other hand, while the plasma MDA level was determined to have increased significantly, erythrocyte SOD and CAT activities were ascertained to have decreased significantly in the group, which was administered sodium fluoride alone on day 30. In the groups, which were administered N-acetylcysteine prior to sodium fluoride, however, it was observed that, after sodium fluoride administration, plasma MDA levels and erythrocyte SOD and CAT activities drew closer to the values of the control group., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Transportations of rivastigmine containing liposomes across Caco-2 cells were studied and in vitro test results were compared with in vivo results. MTT test was used for cell viability studies. Series of formulations were prepared containing rivastigmine which is used for the treatment of Alzheimer's disease. Characterization and stability studies for liposome formulations were performed. Encapsulation efficiencies of liposomes were 35.4%, 25.2% and 29.9% for rivastigmine, rivastigmine-sodium taurocholate, rivastigmine-dimethyl-beta-CD liposomes, respectively. In stability studies, particle size and size distribution, zeta potential, rivastigmine amounts were determined and shelf lives of liposomes were calculated. Penetration properties of rivastigmine through Caco-2 cells, dialysis membrane and kinetics of release from liposomes were determined. Permeability coefficients were calculated after diffusion studies. The highest value of % cumulative amount of rivastigmine passed through caco-2 cell cultures was found to be 87.2% for rivastigmine-sodium taurocholate solution and 12.8% for rivastigmine-sodium taurocholate liposome. The highest permeability coefficient value was obtained with sodium taurocholate liposomes for -0.75. Rivastigmine liposomes and solutions were also applied to animals. Acetyl choline esterase (AChE) activity was determined by the Ellman method on mice. %AChE inhibition values were calculated using blood and brain tissue samples. The physical appearances of the brains were investigated by TEM microscope. The highest value of AChE inhibition was observed for rivastigmine and sodium taurocholate liposomes. The histological investigations and observations also supported these results.

This study was carried out under both light and electron microscopy to investigate the effects on liver carbohydrate and lipid metabolism caused by aflatoxin (AF) fed to chicks. Twenty broiler chicks were used. The birds were housed in electrically heated battery cages and exposed to light for 24 h. Feed and water were provided ad libitum. The animals were allocated to two groups each made up of 10 broilers. Total aflatoxin levels of zero (0) and 5 mg of AF/kg feed (81.05% AFB1, 8.79% AFG1, 6.06% AFB2, and 4.10% AFG2) added to a commercial diet, were fed to chicks from hatching up to 3 weeks of age, when the experiment was terminated. The chicks were executed by cervical dislocation and liver samples were obtained for light and electron microscopy. Oil red 'O', Sudan Black B, periodic acid Schiff (PAS) and Best's carmine stains were used to reveal fat and glycogen in the liver. Histological changes in hepatocytes included increased lipid droplets, high glycogen content, and mild mononuclear cell infiltration in the portal areas. Ultrastructural findings were destruction of rough endoplasmic reticulum (rER), reduction in mitochondrial size, enlargement of bile canaliculi, and cisternal dilatation of the smooth endoplasmic reticulum (sER).

The aim of the study was to determine the penetration properties of various insulin containing liposome formulations through Caco-2 cell monolayer and to compare the in vitro test results with in vivo tests. The effect of sodium taurocholate as a penetration enhancer when it was added to the liposome formulation was also investigated. In vitro permeation experiments were performed in diffusion cells with the Caco-2 cell monolayer used as the membrane. Permeability values of various insulin containing liposome formulations through Caco-2 cells were determined (log k(insulin-solution) = -2.217 +/- 0.0723 cm.h(-1), log k(insulin-liposome) = -2.141 +/- 0.0625 cm.h(-1), log k(insulin-sodium tauroholate liposome)= -1.952 +/- 0.0623 cm.h(-1)). In vivo tests were performed in mice. Formulations were administered orally and blood glucose levels were determined and penetrations were compared with the Caco-2 cell experiment results. In conclusion, the permeability of insulin was increased across Caco-2 cell monolayer when the liposome sodium taurocholate (NaTC) formulation was used. The oral administration of insulin and NaTC incorporated liposomes significantly decreased blood glucose levels. Furthermore, it was shown that a high in vitro/in vivo correlation was observed using the Caco-2 cell monolayer model., (Copyright 2004 Elsevier Inc.)