Cross-linked beta-cyclodextrin microcapsules: preparation and properties.
Microcapsules were prepared by interfacial cross-linking of beta-cyclodextrins (beta-CD) with terephthaloyl chloride (TC). Batches were prepared from beta-CD solutions in 1 M NaOH, using 5% TC and a 30 min reaction time. Microcapsules were studied with respect to morphology (microscopy), size (laser diffraction technique) and, for selected batches, IR spectroscopy, determination of beta-CD content (polarimetry after alkaline dissolution of microcapsules) and complexing properties, evaluated using p-nitrophenol (pNP) as the guest molecule. Well-formed microcapsules were obtained from 5, 7.5, and 10% beta-CD solutions. The mean size of all batches was in the 10-35 microm range. The IR spectrum showed bands at 1724, 1280 and 731 cm(-1), reflecting the formation of esters. The beta-CD contents were 46, 56-58 or 60-66% for batches prepared from 5, 7.5 or 10% beta-CD solutions, respectively. The experiments conducted with 1 mM pNP showed a rapid complexation reaching a maximum within 1 h. When incubating 50 mg lyophilized microcapsules in 10 ml pNP solution, the maximal fixation (97.8 micromol/g microcapsules) was observed for small-sized particles ( approximately 11 microm) prepared from a 7.5% beta-CD solution. The method then appears as a simple and rapid procedure to provide stable microcapsules, having an interesting guest-binding ability.
Pariot
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Laboratoire de Pharmacotechnie, UMR/CNRS 6013, IFR 53, Faculté de Pharmacie, Université de Reims, 51 Rue Cognacq-Jay, F-51096 Cédex, Reims, France.
Edwards-Lévy
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Andry
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Lévy
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D002214:Capsules; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D004339:Drug Compounding; D005503:Food Additives / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry*; D010795:Phthalic Acids / Q000737:chemistry*; D047392:beta-Cyclodextrins
D002214:Capsules; D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D005503:Food Additives; D009596:Nitrophenols; D010795:Phthalic Acids; D047392:beta-Cyclodextrins; C059743:terephthaloyl chloride; C031215:betadex; C024836:4-nitrophenol