Synthesis and characterization of some covalent dextran-polyoxyethyleneglycol derivatives

Duval, Jean Marc; Delestre, Christine; Carré, Marie-Christiane; Hubert, P.; Dellacherie, Édith

doi:10.1016/0144-8617(91)90038-e

Cited by 14 publications

(11 citation statements)

References 12 publications

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“…The cost of amino-terminated PEGs can be prohibitively expensive compared to their hydroxy-terminated counterparts, which may make them inaccessible for some laboratories, or limit large-scale synthesis and use. For the purpose of obtaining larger quantities of amino-terminated polyglycols, we screened published methods describing their synthesis from hydroxyl-terminated polyglycols [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ], for which five approaches have been mainly reported and employed. Several groups have employed a two-step strategy involving the initial conversion of PEG hydroxyl end-groups to phthalimido end-groups via the Mitsunobu reaction followed by the addition of hydrazine to afford amino-terminated PEGs with >98% end-group conversion and isolated yields of 75–88% [ 20 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

“…While the conversion of hydroxyl-terminated PEGs to their corresponding azides has been extensively reported with high isolated yields and quantitative end-group conversion [ 25 , 28 ], their conversion to amines can be more challenging. Therefore, we aimed to identify a novel strategy that would allow the efficient and safe reduction of azides to amines, as well as the facile isolation of the product without contamination.…”

Section: Introductionmentioning

confidence: 99%

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A Facile Strategy for the High Yielding, Quantitative Conversion of Polyglycol End-Groups to Amines

2021

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Amino end-group functionalised polyglycols are important intermediates in the synthesis of sophisticated polymeric architectures and biomaterials. Herein, we report a facile strategy for the end-group conversion of hydroxyl-terminated polyglycols to amino-terminated polyglycols in high isolated yields and with excellent end-group fidelity. Following traditional conversion of polyglycol hydroxyl end-groups to azides via the corresponding mesylate, reduction with zinc in the presence of ammonium chloride afforded a range of amino end-group functionalised poly(ethylene glycol) and poly(propylene glycol) homopolymers and copolymers with isolated yields of 82–99% and end-group conversions of >99% as determined by NMR spectroscopy and MALDI ToF MS. Furthermore, this process is applicable to a sequential reagent addition approach without intermediate polymer isolation steps with only a slight reduction in yield and end-group conversion (95%). Importantly, a simple work-up procedure provides access to high purity polyglycols without contamination from other reagents.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Facile Strategy for the High Yielding, Quantitative Conversion of Polyglycol End-Groups to Amines

2021

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“… 13 , 14 PEG is considered an excellent conjugate for polymer graft materials. 15 , 16 PEG is used to improve the pharmacokinetic properties of biologicals; data show that there is a large therapeutic window of about 600-fold between maximum PEG burden from a biological agent and doses associated with human toxicity. 17 PEG-modulated bioprocessing of PHB produces a natural–synthetic hybrid of PHB- b -PEG with a reduced crystallinity, making this biomaterial relatively less brittle and more flexible than PHB.…”

Section: Introductionmentioning

confidence: 99%

Using Humidity to Control the Morphology and Properties of Electrospun BioPEGylated Polyhydroxybutyrate Scaffolds

et al. 2020

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Electrospinning produces nanofibrous scaffolds with potential for tissue engineering and wound repair. Spinning parameters control scaffold morphology and properties. BioPEGylation of polyhydroxybutyrate (PHB) introduces terminal hydrophilic groups into the hydrophobic chain, making this natural–synthetic hybrid copolymer more susceptible to humidity. Varying the humidity from 10 to 50% RH during electrospinning had a relatively little effect on polyhydroxybutyrate (PHB) average fiber and pore diameters, which remained around 3.0 and 8.7 μm, respectively. In contrast, fiber and pore diameters for electrospun bioPEGylated PHB scaffolds varied significantly with humidity, peaking at 30% RH (5.5 and 14.1 μm, respectively). While scaffolds showed little change, hydrophobicity decreased linearly with humidity during electrospinning. Compared to solvent-cast films, electrospun scaffolds showed significantly greater average cell spread. A 108% increase for olfactory ensheathing cells (OECs) cultivated on bioPEGylated PHB scaffolds was proportionally greater than their counterparts on electrospun PHB scaffolds, (70%). OECS grown on BioPEGylated PHB scaffolds were over twice the size, 260 ± 20 μm diameter, than those on PHB electrospun scaffolds, 110 ± 18 μm diameter. Electrospun scaffolds also promoted cell health compared to their solvent-cast counterparts, with increases in the mitochondrial activity of 165 ± 13 and 196 ± 13% for PHB and bioPEGylated PHB, respectively. OECS cultivated on electrospun scaffolds of bioPEGylated PHB had significantly better membrane integrities compared to their counterparts on solvent-cast films, 47 ± 5% reducing to 17 ± 6%. The combination of bioPEGylation and humidity during electrospinning permitted significant controllable changes to scaffold morphology and properties. These changes resulted in the significantly greater promotion of cell growth on electrospun bioPEGylated PHB scaffolds compared to their solvent-cast counterparts and electrospun PHB.

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“…Several methods had been reported to PEGylate neutral polysaccharides like dextran [20][21][22][23] and inulin. 24,25 Among these methods, the one used in the study, which utilizes a moderate coupling reaction between the hydroxyl-activated polysaccharide and the amino-terminated mPEG, was believed to be more suitable for PEGylation of polysaccharide-based drugs than those that cause charged conjugates 21 or require highly alkaline conditions for the coupling, 23 since it allows the unreacted activated hydroxyls of polysaccharide to return to their original form easily by hydrolysis in a weakly alkaline solution and thus ensures the least influence on the polysaccharide structure and, in turn, on bioactivity. This, coupled with a greater than 1 molar ratio of ROP to mPEG in reaction, makes sure that the conjugates, with mPEG grafting degree of ∼1.0 and thus potentially well preserved bioactivity, were prepared.…”

Section: Preparation Of Pegylated Ropsmentioning

confidence: 99%

Long-circulating delivery of bioactive polysaccharide from radix ophiopogonis by PEGylation

Lin

Wang²,

Huang³

et al. 2011

IJN

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Background: Radix ophiopogonis polysaccharide (ROP) has been found to be effective against myocardial ischemia. One of main problems with its use is its short in-vivo half-life, which makes the development of an effective delivery system necessary. To achieve better therapeutic effects and patient compliance by prolonging its retention in plasma and increasing its distribution in targets, ROP was PEGylated (PEG, polyethylene glycol) in this study. Methods: Through a moderate coupling reaction between hydroxyl-activated ROP and aminoterminated methoxy-PEG (mPEG) (30 or 40 kDa), together with a greater than 1 molar ratio of ROP to mPEG in reaction, long-circulating and potentially bioactive PEGylated ROPs, with PEG grafting number of ∼1.0, were prepared, characterized, and the pharmacokinetics evaluated. Results: Relative to ROP, whose half-life was approximately 0.7 hours, the two conjugates prepared, following intravenous administration, showed markedly prolonged retention in systemic circulation with half-lives in blood of 78.4 and 88.3 hours, respectively. When given subcutaneously, their in-vivo mean residence times were further markedly prolonged by the slow absorption phase. They were found to be well absorbed after subcutaneous administration, with absolute bioavailability being 75.4% and 43.9%, respectively. Conclusion: With apparent molecular masses not exceeding 43 kDa, the conjugates prepared have been and will be demonstrated to have prominent advantages for ROP delivery, such as: the good absorption following subcutaneous, intramuscular, or other ways of administration; the effective utilization of the enhanced permeability and retention effect caused by ischemia; and the rapid diffusion within target tissues.

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Synthesis and characterization of some covalent dextran-polyoxyethyleneglycol derivatives

Cited by 14 publications

References 12 publications

A Facile Strategy for the High Yielding, Quantitative Conversion of Polyglycol End-Groups to Amines

A Facile Strategy for the High Yielding, Quantitative Conversion of Polyglycol End-Groups to Amines

Using Humidity to Control the Morphology and Properties of Electrospun BioPEGylated Polyhydroxybutyrate Scaffolds

Long-circulating delivery of bioactive polysaccharide from radix ophiopogonis by PEGylation

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