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A study of starch addition on burst effect and diameter of polyurethane microspheres containing theophylline
Author(s) -
Emami Shahriar Hojjati,
Orang Fariba,
Mahmoudi Morteza,
Rafienia Mohammad
Publication year - 2008
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.987
Subject(s) - polyurethane , materials science , fourier transform infrared spectroscopy , polycaprolactone , nuclear chemistry , scanning electron microscope , starch , aqueous solution , polymer chemistry , epichlorohydrin , particle size , hexamethylene diisocyanate , theophylline , chemical engineering , chemistry , organic chemistry , composite material , polymer , medicine , engineering , endocrinology
Abstract Theophylline was encapsulated in polyurethane prepared with hexamethylene diisocyanate (HMDI), polycaprolactone (PCL) ( M W = 530 and 2000 g/mol) diols, and starch as polyols and butanediol as chain extender. Polyurethane microspheres were prepared in two reactors; after polyurethane preparation by mixing PCL/starch, HMDI and theophylline in the first reactor, microspheres formation was achieved by transferring the reaction mixture to an aqueous medium (moving at 5000 rpm) of the second reactor. Fourier transform infrared (FTIR) was employed to confirm polyurethane formation during the course of reactions. FTIR spectrum revealed bands at 1729–1733 cm −1 and 3340–3347 cm −1 which indicates carbonyl and NH of amine groups, respectively. Scanning electron microscopy (SEM) was used to study the morphology of the samples. SEM confirmed the formation of microspheres with spherical morphology. Particle size investigation with optical microscopy revealed a size distribution of 8–70 µm. Controlled release of theophylline from the microspheres was performed in phosphate buffered saline (PBS) at pH = 7.4 and monitored with a ultraviolet (UV) spectrometer at 274 nm. Drug release profiles showed that starch addition reduced the release rate around 24% for microspheres prepared from PCL with a molecular weight of 2000 g/mol and it had negligible effect on a molecular weight of 530 g/mol. Copyright © 2007 John Wiley & Sons, Ltd.