New perspective for the treatment of Alzheimer diseases: liposomal rivastigmine formulations

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.

MYCOTOX® and aflatoxicosis in quails

1. This study was to evaluate the toxic effects of aflatoxin (AF) on growth performance of quail, and to determine the preventive efficacy of MYCOTOX (oxicinol, tymol, micronised yeast). 2. One hundred and eighty 1-d-old quail (Coturnix coturnix japonica) of both sexes were weighed and randomly divided into 4 experimental groups each with 5 replicates of 9 birds. 3. There were 4 dietary treatments: (1) control with 0 mg AF/kg diet and 0% MYCOTOX; (2) 0 mg AF/kg diet and 0.5% MYCOTOX; (3) 2.5 mg AF/kg diet and 0% MYCOTOX; (4) 2.5 mg AF/kg diet plus 0.5% MYCOTOX. The chicks were maintained on these treatments to 3 weeks of age. Quail consumed the diets and water ad libitum. 4. Body weight (BW) gains in groups receiving AF alone were the lowest at all periods. Feed intake was lowest in the group consuming the AF diet. The addition of MYCOTOX to the AF diet did not prevent or reduce the toxic effects of AF on feed intake at any time period. Feeding diets containing MYCOTOX alone did not change feed intake significantly. With the exception of the 1 to 7 d period, feed conversion of chicks fed the AF diet was similar to those of the other experimental groups. 5. Bursa of Fabricius weight decreased, whereas the relative weights of liver, kidney and spleen increased in quail consuming diets containing AF and AF plus MYCOTOX. Liver colour was normal in the control and MYCOTOX alone group, but was lighter in groups fed AF. 6. The results indicated that MYCOTOX was not effective in preventing the deleterious effects of AF.

Investigation of liposome formulation effects on rivastigmine transport through human colonic adenocarcinoma cell line (CACO-2)

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.

Light and electron microscopic studies on liver histology in chicks fed aflatoxin

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 effect of various liposome formulations on insulin penetration across Caco-2 cell monolayer

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.