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A pH‐Triggered Polymer Degradation or Drug Delivery System by Light‐Mediated Cis / Trans Isomerization of o ‐Hydroxy Cinnamates
Author(s) -
Abramov Alex,
Maiti Binoy,
Keridou Ina,
Puiggalí Jordi,
Reiser Oliver,
Díaz David Díaz
Publication year - 2021
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.202100213
Subject(s) - polymer , chemistry , polyethylene glycol , cinnamates , isomerization , monomer , peg ratio , moiety , photochemistry , polymer degradation , ethylene glycol , polymer chemistry , photodegradation , organic chemistry , photocatalysis , finance , economics , catalysis
A new methodology for the pH‐triggered degradation of polymers or for the release of drugs under visible light irradiation based on the cyclization of ortho ‐hydroxy‐cinnamates ( o HC) to coumarins is described. The key o HC structural motif can be readily incorporated into the rational design of novel photocleavable polymers via click chemistry. This main‐chain moiety undergoes a fast photocleavage when irradiated with 455 nm light provided that a suitable base is added. A series of polyethylene glycol‐ alt ‐ ortho ‐hydroxy cinnamate (polyethylene glycol (PEG) n ‐ alt ‐ o HC)‐based polymers are synthesized and the time‐dependent visible‐light initiated cleavage of the photoactive monomer and polymer is investigated in solution by a variety of spectroscopic and chromatographic techniques. The photo‐degradation behavior of the water‐soluble poly(PEG 2000 ‐ alt ‐ o HC) is investigated within a broad pH range (pH = 2.1–11.8), demonstrating fast degradation at pH 11.8, while the stability of the polymer is greatly enhanced at pH 2.1. Moreover, the neat polymer shows long‐term stability under daylight conditions, thus allowing its storage without special precautions. In addition, two water‐soluble PEG‐based drug‐carrier molecules (mPEG 2000 ‐ o HC‐benzhydrol/phenol) are synthesized and used for drug delivery studies, monitoring the process by UV–vis spectroscopy in an ON/OFF intermittent manner.