- pH-responsive chitosan nanoparticles from a novel twin-chain anionic amphiphile for controlled and targeted delivery of vancomycin
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The design and synthesis of novel pH-responsive nanoantibiotics is an emerging research area to address the antibiotic resistance crisis. The purpose of this study was therefore to synthesize a new anionic gemini surfactant (AGS) that could result in the formulation of pH-responsive chitosan nanoparticles (CSNPs) to treat methicillin-resistant Staphylococcus aureus (MRSA) infections. The coupling of oleic acid with 2,2-dimethyl-5,5-bis(hydroxymethyl)-1,3-dioxane and subsequent deprotection followed by a reaction with succinic anhydride and sodium bicarbonate yielded AGS. Critical micelle concentration (CMC) was determined using conductometry and in vitro cytotoxicity was performed using a MTT assay. Vancomycin loaded CSNPs containing AGS (DL_CSSNPs) were prepared by ionotropic gelation of chitosan with pentasodium tripolyphosphate. CSNPs were characterized for size, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, surface morphology, in vitro drug release and in vitro antibacterial activity (at pH 6.5 and 7.4). Results from the in vitro antibacterial activity were further supported by an in vivo study using a mice skin infection model. The CMC of AGS was found to be 1.3?mM/L and it was non-toxic. The DL_CSSNPs were spherical with size, PDI and ZP of 220.57?±?5.9?nm, 0.299?±?0.004 and 21.9?±?0.9?mV respectively. An increase in the vancomycin release from the DL_CSSNPs was observed at pH 6.5 compared to pH 7.4. The minimum inhibitory concentration values at pH 6.5 and 7.4 against MRSA were 7.81 and 62.5?μg/ml respectively. In vivo antibacterial activity showed that the MRSA burden in mice treated with DL_CSSNPs was reduced by almost 8-fold compared to those treated with pure vancomycin.
- Kalhapure, Rahul S.,Jadhav, Mahantesh,Rambharose, Sanjeev,Mocktar, Chunderika,Singh, Sanil,Renukuntla, Jwala,Govender, Thirumala
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- Size selectivity in lipase catalysed tetrol acylation
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Size selectivity of Candida antarctica lipase B (CAL-B) was examined in the acylation of pentaerythritol with oleic acid. Biolubricant mixtures consisting of mono-, di-, tri-, and tetraoleates were expected in variable excess. Enzymatic tetraoleate format
- Happe, Manuel,Kouadio, Martial,Treanor, Christopher,Sawall, Jan-Phillip,Fornage, Antoine,Sugnaux, Marc,Fischer, Fabian
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- Size selectivity in lipase catalysed tetrol acylation
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Size selectivity of Candida antarctica lipase B (CAL-B) was examined in the acylation of pentaerythritol with oleic acid. Biolubricant mixtures consisting of mono-, di-, tri-, and tetraoleates were expected in variable excess. Enzymatic tetraoleate formation was suppressed under solvent conditions; however, this size selectivity was lost without solvent and tetra-acylated pentaerythritol accumulated in up to 93%. The lipase caused size selectivity persisted over a broad temperature range from 35 to 95 °C. A Fischer-Speier esterification showed that substrate bulkiness was only a minor contributor to observed size selectivity. All in all, switch on/off size selectivity using CAL-B allowed to vary pentaerythritol biolubricant compositions in an unprecedented manner.
- Happe, Manuel,Kouadio, Martial,Treanor, Christopher,Sawall, Jan-Phillip,Fornage, Antoine,Sugnaux, Marc,Fischer, Fabian
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- ESTERS FROM SOLID POLYOLS AND UNSATURATED CARBOXYLIC ACIDS
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The present invention relates to a process for the preparation of an ester from a polyol which is solid at 25° C. and a carboxylic acid component which contains at least 50 wt. % of at least one mono- or polyunsaturated aliphatic carboxylic acid, based on the total weight of the carboxylic acid component, in a reactor under reduced pressure. The invention also provides a device, a process for the preparation of a thermoplastic composition comprising the ester prepared according to the invention, a process for the production of a shaped article comprising the ester according to the invention or the thermoplastic composition according to the invention, a process for the production of a packed product, a process for the production of an at least partly coated object, and uses of the esters according to the invention as an additive in various compositions.
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Paragraph 0280
(2013/03/26)
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- A versatile synthesis of tetraester polyamine lipids for gene transfection
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The preparation of polyamine lipids via Michael addition of diamines to tetraester bisacrylates is described. A new pentaerythritol protection strategy enabled the synthesis of a bis(p-methoxybenzyl)diether diol which was used to prepare the saturated and unsaturated diester cores.
- Lizarzaburu, Mike E.,Kurth, Mark J.,Nantz, Michael H.
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p. 8985 - 8988
(2007/10/03)
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