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pH‐responsive release from polypeptide microcapsules
Author(s) -
Kidchob T.,
Kimura S.,
Imanishi Y.
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970124)63:4<453::aid-app6>3.0.co;2-q
Subject(s) - membrane , chemistry , permeation , carboxylate , polymer chemistry , dextran , ammonium , peptide , stereochemistry , chromatography , organic chemistry , biochemistry
Microcapsules were prepared from [Glu(OMe)] m (Sar) n (m = 21, n = 19) and [Lys(Z)] m (Sar) n (m = 27, n = 15), and were chemically modified to obtain a pH‐responsive releasing membranes. One membrane was prepared by partially deprotecting the ester groups of [Glu(OMe)] m (Sar) n . The other membrane was prepared by connecting of poly(Glu) to side chain amino groups that were generated by a partial deprotection of [Lys(Z)] m (Sar) n . Consequently, two types of polypeptidic microcapsules were prepared; Glu residues in the main chain, and Glu residues in the graft chains on the positively charged main chain. Both microcapsules showed pH‐responsive release of FITC‐dextran encapsulated in the microcapsules. The release rate became slower in the medium at pH 3.0 than pH 7.5. Optical microscope observation revealed that partially deblocked [Glu(OMe)] m (Sar) n microcapsules swelled more at pH 7.5 than at pH 3.0; hence, enhanced permeation through the polypeptide membrane at pH 7.5. However, the shape of poly(Glu)‐grafted [Lys(Z)] m (Sar) n microcapsules changed a little by changing pH of the medium. It is suggested that ion‐pairing between carboxylate groups of poly(Glu) and ammonium groups of Lys acts as crosslinking to give the shape stability. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 453–458, 1997