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| 2. |
- Lazorova, Lucia, et al.
(author)
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Transport of an influenza virus vaccine formulation (iscom) in Caco-2 cells
- 1996
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In: American Journal of Physiology. - 0002-9513 .- 2163-5773. ; 270:4, s. G554-G564
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Journal article (peer-reviewed)abstract
- The influenza virus envelope glycoproteins hemagglutinin and neuraminidase were administered to the apical or basolateral sides of Caco-2 monolayers either as native protein micelles (mic-ag) or after incorporation into the orally active adjuvant formulation, immune stimulating complexes (iscoms) (isc-ag). Biotin-conjugated isc-ag were localized in intracellular vesicles as early as 2 min after administration to the apical side at 37 degrees C. Ten minutes after administration, both intracellular vesicles and intercellular spaces were labeled, and extracellular labeling was observed on the basolateral side of the cells, indicating that isc-ag were transported across the epithelium within 10 min of exposure. Transport of 125I-labeled isc-ag and mic-ag in the apical-to-basolateral and basolateral-to-apical directions across Caco-2 monolayers was comparable at 37 degrees C. Gel chromatography analysis revealed that only 0.55-3.1% of transported isc-ag and mic-ag had a molecular weight of > 5,000, while 21.0-42.3% was eluted at a position corresponding to peptides of approximately 10 amino acids. Although isc-ag and mic-ag were transported and degraded by Caco-2 monolayers in comparable amounts, only transported isc-ag induced a dose-dependent proliferative response in vitro of T cells primed with influenza virus antigen. High-performance gel chromatography and reverse-phase high-performance liquid chromatography indicated that transported antigenic isc-ag consisted of hydrophobic peptides with a molecular weight of < or = 3,000. These results indicate that antigens incorporated into the orally active adjuvant formulation iscom are degraded to antigenic peptides during transport across the intestinal epithelium.
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| 3. |
- Lindmark, T, et al.
(author)
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Absorption enhancement in intestinal epithelial Caco-2 monolayers by sodium caprate : Assessment of molecular weight dependence and demonstration of transport routes
- 1998
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In: Journal of drug targeting (Print). - : Informa UK Limited. - 1061-186X .- 1029-2330. ; 5:3, s. 215-223
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Journal article (peer-reviewed)abstract
- Sodium caprate (CIO), a medium chain fatty acid, is used clinically to enhance rectal absorption of the low molecular weight (MW) drug ampicillin. The main aim of this study was to investigate whether CIO also enhances the permeability of high MW model drugs in a model of the intestinal epithelium. The second aim was to present visual evidence of the route of enhanced transport across the epithelial cell layer. The studies were performed in Caco-2 monolayers cultured on permeable supports. The effects of non-toxic concentrations (≤ 13 mM) of CIO on drug transport across the monolayers was studied using monodisperse 14C-polyethylene glycols (MW 238-502; 14C-PEGs), 125I-Arg8-vasopressin (MW 1,208), 125I-insulin (MW 6,000) and FITC-labelled dextrans (MW 4,400 and 19,600; FD4 and FD20 respectively) as model drugs. Electron and confocal laser scanning microscopy were used to demonstrate transport routes across the epithelium. 10 mM C10 increased the permeability of all 14C-PEGs to approximately the same extent. 13 mM C10 increased the permeability of 125I-Arg8-vasopressin 10-fold. Only small increases in FD4 and FD20 permeabilities were observed. After C10 exposure, both tight junctions with normal morphology and those with dilatations showed an increased permeability to ruthenium red, indicating that C10 enhanced the paracellular transport of molecules with a MW < 1,000. Confocal microscopy showed that C10 increased the transport of FD4 and FD20 by the paracellular route. In conclusion, nontoxic concentrations of C10 can be used to enhance the permeability of drugs of MW up to approximately 1,200. Enhancement of the absorption of molecules larger than 4,000 is quantitatively insignificant. The enhanced permeability occurred via the paracellular pathway.
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| 5. |
- Sturesson, Cecilia, et al.
(author)
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Encapsulation of rotavirus into poly(lactide-co-glydolide) microspheres
- 1999
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In: Journal of Controlled Release. - 0168-3659 .- 1873-4995. ; 59:3, s. 377-389
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Journal article (peer-reviewed)abstract
- Two small-scale double emulsion techniques for incorporation of formaldehyde-inactivated rotavirus particles (FRRV) into poly(lactide-co-glycolide) (PLG) microspheres were developed and optimised. The effects of high-speed homogenisation versus vortex mixing on the double emulsion stability, microsphere size, entrapment efficiency and in vitro release of FRRV in the second emulsification step were studied. A stable double emulsion was verified only when using vortex mixing in this step. Slow removal of the organic phase allowed measurement of the size of the emulsion droplets and subsequent prediction of the size of the resulting microspheres. Microspheres in the size range of 1-10 microm were prepared using both techniques. The homogenisation technique was sensitive to changes in the operating time, the emulsification energy and the volume of the outer aqueous phase, while the vortex technique was more robust. Rotavirus was released in vitro in a triphasic manner with both techniques. The more robust vortex technique was selected for preparation of PLG microspheres containing rotavirus for in vivo studies. After immunisation of mice with a single intramuscular injection, the PLG-FRRV microspheres elicited an IgG antibody response in serum detected by ELISA equally high as that elicited with FRRV alone. These results indicate that the antigenicity of FFRV was retained after incorporation into PLG microspheres using the vortex technique.
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| 7. |
- Toth, I, et al.
(author)
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Novel lipoamino acid- and liposaccharide-based system for peptide delivery : Application for oral administration of tumor-selective somatostatin analogues
- 1999
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 42:19, s. 4010-1013
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Journal article (peer-reviewed)abstract
- Lipoamino acid and liposaccharide conjugates of somatostatin analogue TT-232 were synthesized to modify the physicochemical properties of the parent peptide. The relative position, the number, and the nature of the lipid and/or saccharide moieties were varied. Experiments in vitro clearly showed that many compounds modified at the N- and/or C-terminus with lipid or sugar moieties retained the biological activity of the parent compound. An interesting construct was synthesized containing lipid and sugar units at opposite ends of the somatostatin analogue, so that the entire molecule could be considered as an amphipathic surfactant.
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