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Novel Alginate‐Poly( L ‐histidine) Microcapsules as Drug Carriers: In Vitro Protein Release and Short Term Stability
Author(s) -
Wang ShiBin,
Xu FeiHai,
He HongShan,
Weng LianJin
Publication year - 2005
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200400204
Subject(s) - chemistry , calcium alginate , hydrochloric acid , kinetics , aqueous solution , nuclear chemistry , calcium , histidine , particle size , phosphate buffered saline , in vitro , chromatography , controlled release , polymer chemistry , chemical engineering , biochemistry , amino acid , organic chemistry , physics , quantum mechanics , engineering
Summary: Spherical, smooth‐surfaced and mechanically stable alginate‐poly( L ‐histidine) (PLHis) microcapsules with narrow particle size distributions were prepared by incubating calcium alginate beads in aqueous solutions of PLHis. The in vitro release characteristics, drug loading and encapsulation efficiency of the microcapsules were investigated using bovine erythrocytes hemoglobin (Hb) as a model drug. The results showed that the concentration of Ca 2+ ions had a considerable effect on the drug loading, encapsulation efficiency and in vitro release behavior of the microcapsules. When the concentration of CaCl 2 in the PLHis solution was increased from 0 to 3.0% (w/v), the drug loading and encapsulation efficiency decreased significantly from 38.0 to 4.3% and from 92.9 to 8.0%, respectively, while the total cumulative release of Hb from microcapsules in phosphate buffered saline solution (PBS, pH 6.8) decreased from 96.2 to 72.8% in 24 h. No significant protein release was observed during 70 h of incubation in hydrochloric acid solution (pH 1.2). However, under neutral conditions (PBS, pH 6.8), the Hb was completely and stably released within 24–70 h. An explosion test showed that the stability of alginate‐PLHis microcapsules depended strongly on the concentration of PLHis and the calcium ions in solution.Microscopy photo of Hb‐loaded alginate‐PLHis microcapsules.