- Large-scale synthesis of α-amino acid-N-carboxyanhydrides
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Hetero- and homopolymers prepared from α-amino acid-N-carboxyanhydrides (NCAs) monomers are widely useful products. The preparation of pure NCA monomers has been extensively studied in the past. Purification methods including repeated crystallizations, extraction, and flash column chromatography have been devised. However, these methods are not easily amendable to large-scale NCA preparations. This article describes the synthesis of numerous highly purified NCAs on a >100 g scale using a simple filtration step through diatomaceous earth (celite). The resulting NCAs provided polyethylene glycol (PEG)–amino acid triblock polymers devoid of low-molecular-weight by-products that were routinely observed when unfiltered batches of NCAs were used. Also disclosed is the preparation of NCAs at ambient temperature. Traditionally, NCA reactions using a phosgene source are heated. This study shows these reactions can be driven by the slight exotherm that forms upon reagent mixing. This eliminates the need for an external heating source, simplifying large-scale reactions.
- Semple, J. Edward,Sullivan, Bradford,Sill, Kevin N.
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- Terpolymerization kinetics of amino acid N-carboxy anhydrides
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Based on their versatility with respect to amino acid type and sequence, polypeptides have become attractive for a number of biological applications such as drug delivery, biomineralization, and drugs. N-carboxy anhydride (NCA) polymerization is a convenient way to rapidly prepare high-molecular weight polypeptides with good control over molecular weight and polydispersity. However, the kinetics of the incorporation of NCA monomers into copolypeptides during random copolymerization are poorly understood. Here, kinetic data is presented that allows insight into the NCA polymerization of a terpolymer composed of three commercially relevant amino acids, namely, glutamic acid, lysine, and tyrosine. Furthermore, kinetic data and copolymerization parameters from the copolymerization of binary mixtures of these three amino acid NCAs is used to make predictions of the terpolymer composition. This study provides access to the information necessary to prepare functional copolypeptides with better-defined sequence architecture that will be essential for the future development of polypeptide-based materials.
- Zelzer, Mischa,Heise, Andreas
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p. 1228 - 1236
(2014/04/17)
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- COPOLYMERS FOR STABLE MICELLE FORMULATIONS
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The present invention relates to the field of polymer chemistry and more particularly to multiblock copolymers and micelles comprising the same. Compositions herein are useful for drug-delivery applications.
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Paragraph 0357; 0358; 0359
(2014/09/29)
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- BLOCK COPOLYMERS FOR STABLE MICELLES
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The present invention relates to the field of polymer chemistry and more particularly to multiblock copolymers and micelles comprising the same. Compositions herein are useful for drug-delivery applications.
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Paragraph 0390; 0391
(2013/11/05)
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- Supramolecular hydrogels with reverse thermal gelation properties from (Oligo)tyrosine containing block copolymers
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Novel block copolymers comprising poly(ethylene glycol) (PEG) and an oligo(tyrosine) block were synthesized in different compositions by N-carboxyanhydride (NCA) polymerization. It was shown that PEG2000-Tyr 6 undergoes thermoresponsive hydrogelation at a low concentration range of 0.25-3.0 wt % within a temperature range of 25-50 C. Cryogenic transmission electron microscopy (Cryo-TEM) revealed a continuous network of fibers throughout the hydrogel sample, even at concentrations as low as 0.25 wt %. Circular dichroism (CD) results suggest that better packing of the β-sheet tyrosine block at increasing temperature induces the reverse thermogelation. A preliminary assessment of the potential of the hydrogel for in vitro application confirmed the hydrogel is not cytotoxic, is biodegradable, and produced a sustained release of a small-molecule drug.
- Huang, Jin,Hastings, Conn L.,Duffy, Garry P.,Kelly, Helena M.,Raeburn, Jaclyn,Adams, Dave J.,Heise, Andreas
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p. 200 - 206
(2013/03/14)
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- POLYMER MICELLES CONTAINING ANTHRACYLINES FOR THE TREATMENT OF CANCER
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The present invention provides micelles having an anthracycline encapsulated therein, the micelles comprising a multiblock copolymer. The invention further provides methods of preparing and using said micelles, and compositions thereof.
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Page/Page column 60
(2010/11/17)
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- HYBRID BLOCK COPOLYMER MICELLES WITH MIXED STEREOCHEMISTRY FOR ENCAPSULATION OF HYDROPHOBIC AGENTS
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The present invention relates to the field of polymer chemistry and more particularly to multiblock copolymers and micelles comprising the same.
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Page/Page column 95
(2008/12/08)
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- THE PREPARATION OF N-CARBOXYANHYDRIDES OF α-AMINO ACIDS USING BIS(TRICHLOROMETHYL)CARBONATE
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A syntheis of the N-carboxyanhydrides (NCA's) of several α-amino acids using bis(trichloromethyl)carbonate, 1, is reported.The triphosgene is used to supply phosgene in situ in stoichiometric amounts; it is particularly effective for preparing NCA's of amino acids with long, aliphatic side chains.
- Daly, William H.,Poche, Drew
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p. 5859 - 5862
(2007/10/02)
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