A pH-triggered polymer degradation or drug delivery system by light-mediated cis/trans isomerization of o-hydroxy cinnamates
A new methodology for the pH-triggered degradation of polymers or for therelease of drugs under visible light irradiation based on the cyclization ofortho-hydroxy-cinnamates (oHC) to coumarins is described. The key oHCstructural motif can be readily incorporated into the rational design of novelphot...
| Authors: | , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2021 |
| Country: | España |
| Institution: | Universidad de La Laguna (ULL) |
| Repository: | RIULL. Repositorio Institucional de la Universidad de La Laguna |
| OAI Identifier: | oai:riull.ull.es:915/42193 |
| Online Access: | http://riull.ull.es/xmlui/handle/915/42193 |
| Access Level: | Open access |
| Keyword: | Polymer degradation Cis/Trans isomerization o-Hydroxy cinnamates drugs visible light irradiation |
| Summary: | A new methodology for the pH-triggered degradation of polymers or for therelease of drugs under visible light irradiation based on the cyclization ofortho-hydroxy-cinnamates (oHC) to coumarins is described. The key oHCstructural motif can be readily incorporated into the rational design of novelphotocleavable polymers via click chemistry. This main-chain moietyundergoes a fast photocleavage when irradiated with 455 nm light providedthat a suitable base is added. A series of polyethylene glycol-alt-ortho-hydroxycinnamate (polyethylene glycol (PEG)n-alt-oHC)-based polymers aresynthesized and the time-dependent visible-light initiated cleavage of thephotoactive monomer and polymer is investigated in solution by a variety ofspectroscopic and chromatographic techniques. The photo-degradationbehavior of the water-soluble poly(PEG2000 -alt-oHC) is investigated within abroad 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, theneat polymer shows long-term stability under daylight conditions, thusallowing its storage without special precautions. In addition, twowater-soluble PEG-based drug-carrier molecules(mPEG 2000 -oHC-benzhydrol/phenol) are synthesized and used for drugdelivery studies, monitoring the process by UV–vis spectroscopy in anON/OFF intermittent manner. |
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