title: Biocatalytic route to sugar-PEG-based polymers for drug delivery applications.
abstract: Sugar-PEG-based polymers were synthesized by enzymatic copolymerization of 4-C-hydroxymethyl-1,2-O-isopropylidene-β-L-threo-pentofuranose/4-C-hydroxymethyl-1,2-O-benzylidene-β-L-threo-pentofuranose/4-C-hydroxymethyl-1,2-O-isopropylidene-3-O-pentyl-β-L-threo-pentofuranose with PEG-600 dimethyl ester using Novozyme-435 (Candida antarctica lipase immobilized on polyacrylate). Carbohydrate monomers were obtained by the multistep synthesis starting from diacetone-D-glucose and PEG-600 dimethyl ester, which was in turn obtained by the esterification of the commercially available PEG-600 diacid. Aggregation studies on the copolymers revealed that in aqueous solution those polymers bearing the hydrophobic pentyl/benzylidene moiety spontaneously self-assembled into supramolecular aggregates. The critical aggregation concentration (CAC) of polymers was determined by surface tension measurements, and the precise size of the aggregates was obtained by dynamic light scattering. The polymeric aggregates were further explored for their drug encapsulation properties in buffered aqueous solution of pH 7.4 (37 °C) using nile red as a hydrophobic model compound by means of UV/vis and fluorescence spectroscopy. There was no significant encapsulation in polymer synthesized from 4-C-hydroxymethyl-1,2-O-isopropylidene-β-L-threo-pentofuranose because this sugar monomer does not contain a big hydrophobic moiety as the pentyl or the benzylidene moiety. Nile red release study was performed at pH 5.0 and 7.4 using fluorescence spectroscopy. The release of nile red from the polymer bearing benzylidene moiety and pentyl moiety was observed with a half life of 3.4 and 2.0 h, respectively at pH 5.0, whereas no release was found at pH 7.4.
authors.affiliation: Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi 110 007, India.
authors.forename: Sumati
authors.initials: S
authors.lastname: Bhatia
authors.forename: Andreas
authors.initials: A
authors.lastname: Mohr
authors.forename: Divya
authors.initials: D
authors.lastname: Mathur
authors.forename: Virinder S
authors.initials: VS
authors.lastname: Parmar
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Prasad
mesh_terms: D055162:Biocatalysis; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism; D004339:Drug Compounding; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D005947:Glucose / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008027:Light; D008049:Lipase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010078:Oxazines / Q000032:analysis / Q000378:metabolism; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism; D058105:Polymerization; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D008823:Micelles; D010078:Oxazines; D011134:Polysaccharides; D011092:Polyethylene Glycols; C036124:1,2-5,6-di-O-isopropylidene-D-glucofuranose; C093667:Novozyme 435; D008049:Lipase; D005947:Glucose; C044808:nile red