Human growth hormone-loaded nanogels composed of cinnamoyl alginate, cinnamoyl Pluronic F127, and cinnamoyl poly(ethylene glycol)

초록

Cinnamoyl alginate (CinAlg), cinnamoyl Pluronic F127 (CinPlu), and cinnamoyl poly(ethylene glycol) (CinPEG) could be self-assembled into nanogels, possibly due to hydrophobic interaction among cinnamic acid (CA) residues. The nanogels were nearly spherical particles on TEM photographs. The photodimerization of CA residue had little effect on the integrity and the size of nanogel. The stability of the nanogels in blood plasma for 48 h at 37 degrees C did not depend on UV irradiation, however they were stable in deoxycholate solution (1 and 10 mM) only when they were UV-treated. Human growth hormone (hGH) could readily be loaded in the nanogel under an acidic condition possibly due to the electrostatic interaction between hGH and CinAlg. hGH hardly released from the nanogel at body temperature (37 degrees C) when the release medium was at acidic condition (e.g., pH 3.0, pH 5.0; <10% in 170 h). However, it readily released at the same temperature when the medium was at physiological pH (e.g., pH 7.4; around 45% in 170 h) and at an alkaline condition (e.g., pH 9.0; >50% in 170 h). However, slow release of hGH was observed for 100 h possibly due to the layer of thermally condensed Pluronic F127 chains. In addition, initial burst release was suppressed as the CinPlu content increased. For example, the release degree at pH 9 in 60 min decreased from 15.3 to 5.9% as the CinPlu content increased from 20 to 60%. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42446.

키워드