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Synthesis of Highly pH‐Responsive Glucose Poly(orthoester)
Author(s) -
Li Lingyao,
Xu Yi,
Milligan Ian,
Fu Liye,
Franckowiak Emily A.,
Du Wenjun
Publication year - 2013
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201306391
Subject(s) - orthoester , chemistry , monomer , polymer , bromide , iodide , condensation polymer , polymer chemistry , sugar , organic chemistry , combinatorial chemistry
pH‐Responsive polymers have great potential in biomedical applications, including the selective delivery of preloaded drugs to tissues with low pH values. These polymers usually contain acid‐labile linkages such as esters and acetals/ketals. However, these linkages are only mildly pH‐responsive with relatively long half‐lives ( t 1/2 ). Orthoester linkages are more acid‐labile, but current methods suffer from synthetic challenges and are limited to the availability of monomers. To address these limitations, a sugar poly(orthoester) was synthesized as a highly pH‐responsive polymer. The synthesis was achieved by using 2,3,4‐tri‐ O‐ acetyl‐α‐ D ‐glucopyranosyl bromide as a difunctional AB monomer and tetra‐ n ‐butylammonium iodide (TBAI) as an effective promoter. Under optimal conditions, polymers with molecular weights of 6.9 kDa were synthesized in a polycondensation manner. The synthesized glucose poly(orthoester), wherein all sugar units were connected through orthoester linkages, was highly pH‐responsive with a half‐life of 0.9, 0.6, and 0.2 hours at pH 6, 5, and 4, respectively.