| 1. |
- Awad, Doaa, et al.
(författare)
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Halogenated Dodecaborate Clusters as Agents to Trigger Release of Liposomal Contents
- 2015
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Ingår i: ChemPlusChem. - : Wiley. - 2192-6506. ; 80:4, s. 656-664
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Tidskriftsartikel (refereegranskat)abstract
- Halogenated dodecaborates, and especially dodecaiodododecaborate(2−), are found to trigger effectively the release of the contents of phospholipid liposomes, including liposomes containing distearoylphosphatidylcholine and cholesterol, which are used clinically in cancer therapy. The basis of the release is studied through differential scanning calorimetry, cryo-transmission electron microscopy, and atomic force microscopy. Upon administration at high concentrations, drastic morphological changes are induced by the dodecaborates. Their possible use in triggered release is suggested.
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| 2. |
- Gabel, Detlef, et al.
(författare)
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The Anionic Boron Cluster (B(12)H(11)SH)(2-) as a Means To Trigger Release of Liposome Contents.
- 2007
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Ingår i: ChemMedChed. - : Wiley. - 1860-7179. ; 2:1, s. 51-53
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Tidskriftsartikel (refereegranskat)abstract
- Triggered release. Liposomes are novel carriers for pharmaceutical agents and can be triggered to release their contents by the addition of B12H11SH, a compound in clinical use. As systemic toxicity is decreased relative to the free drug, liposomal drugs can therefore be administered in higher concentrations before dose-limiting side effects are met. Thus, liposome-encapsulated drugs may be of great value in the therapy of diseases.
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| 3. |
- Justus, Eugen, et al.
(författare)
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Synthesis, liposomal preparation, and in vitro toxicity of two novel dodecaborate cluster lipids for boron neutron capture therapy
- 2007
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Ingår i: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 18:4, s. 1287-1293
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Tidskriftsartikel (refereegranskat)abstract
- A new class of lipids, contg. the closo-dodecaborate cluster, has been synthesized. Two lipids, S-(N, N-(2-dimyristoyloxyethyl)acetamido)thioundecahydro-closo-dodecaborate (2-) (B-6-14) and S-(N, N-(2-dipalmitoyloxyethyl)acetamido)thioundecahydro-closo-dodecaborate (2-) (B-6-16) are described. Both of them have a double-tailed lipophilic part and a headgroup carrying two neg. charges. Differential scanning calorimetry shows that B-6-14 and B-6-16 bilayers have main phase transition temps. of 18.8 and 37.9 DegC, resp. Above the transition temp. of 18.8 DegC, B-6-14 can form liposomal vesicles, representing the first boron-contg. lipid with this capability. Upon cooling below the transition temp., stiff bilayers are formed. When incorporated into liposomal formulations with equimolar amts. of distearoyl phosphatidylcholine (DSPC) and cholesterol, stable liposomes are obtained. The z-potential measurements indicate that both B-6-14- and B-6-16-contg. vesicles are neg. charged, with the most neg. potential described of any liposome so far. The liposomes are of high potential value as transporters of boron to tumor cells in treatments based on boron neutron capture therapy (BNCT). Liposomes prepd. from B-6-14 were slightly less toxic in V79 Chinese hamster cells (IC50 5.6 mM) than unformulated Na2B12H11SH (IC50 3.9 mM), while liposomes prepd. from B-6-16 were not toxic even at 30 mM.
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| 4. |
- Schaffran, Tanja, et al.
(författare)
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Dodecaborate cluster lipids with variable headgroups for boron neutron capture therapy : Synthesis, physical-chemical properties and toxicity
- 2009
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Ingår i: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X .- 1872-8561. ; 694:11, s. 1708-1712
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Tidskriftsartikel (refereegranskat)abstract
- We have prepared two new boron-containing lipids with potential use in boron neutron capture therapy of tumors. These lipids consist of a diethanolamine frame with two myristoyl chains bonded as esters, and a butylene or ethyleneoxyethylene unit linking the doubly negatively charged dodecaborate cluster to the amino function of the frame, obtained by nucleophilic attack of the amino on the tetrahydrofurane and dioxane derivatives, respectively, of closo-dodecaborate. The latter cluster lipid can form liposomes at 25 °C whereas the former lipid at this temperature assembles into bilayer disks. Both lipids form stable liposomes when mixed with suitable helper lipids. The thermotropic behavior was found to be different for the two lipids, with the butylene lipid showing sharp melting transitions at surprisingly high temperatures. Toxicity in vitro and in vivo varies greatly, with the butylene derivative being more toxic than the ethyleneoxyethylene derivative.
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| 5. |
- Schaffran, Tanja, et al.
(författare)
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Interaction of N,N,N-trialkylammonioundecahydro-closo-dodecaborates with dipalmitoyl phosphatidylcholine liposomes
- 2010
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Ingår i: Chemistry and Physics of Lipids. - : Elsevier BV. - 0009-3084 .- 1873-2941. ; 163:1, s. 64-73
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Tidskriftsartikel (refereegranskat)abstract
- N,N,N-Trialkylammonioundecahydrododecaborates (1-), a novel class of compounds of interest for use as anions in ionic liquids, interact with DPPC liposomes. Increasing compound concentration causes an increasing negative zeta potential. Dissociation constants demonstrate that the binding capacity increases strongly with longer chain length. N,N,N-Trialkylammonioundecahydrododecaborates with longer alkyl chains show a detergent-like behavior: the compounds incorporate into the liposome membrane and differential scanning calorimetric experiment show already low concentrations cause a complete disappearance of the peak representing the gel-to-liquid crystalline phase transition. In contrast, compounds with shorter alkyl chains only interact with the headgroups of the lipids. Investigations by means of cryo-TEM reveal that all derivatives induce significant morphological changes of the liposomes. N,N,N-Trialkylammonioundecahydrododecaborates with short alkyl chains produce large bilayer sheets, whereas those with longer alkyl chains tend to induce the formation of open or multi-layered liposomes. We propose that the binding of N,N,N-trialkylammonioundecahydrododecaborates is mainly due to electrostatic interactions between the doubly negatively charged cluster unit and the positively charged choline headgroup; the positively charged ammonium group might be in contact with the deeper-lying negatively charged phosphate. For N,N,N-trialkylammonioundecahydrododecaborates with longer alkyl chains hydrophobic interactions with the non-polar hydrocarbon part of the membrane constitute an additional important driving force for the association of the compounds to the lipid bilayer.
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