Photoinitiated Synthesis of a Covalent Pullulan and Beta Cyclodextrin Conjugate in Supercritical Carbon Dioxide

Abstract

A three-stage route is proposed for the preparation of a covalent pullulan-beta-cyclodextrin conjugate through carboxymethylation of beta-cyclodextrin, EDC/NHS-mediated coupling with cysteamine, allylation of pullulan, and photoinitiated thiol-ene conjugation in a supercritical carbon dioxide-containing medium. A critical stoichiometric review identified an inconsistency between the reported allyl substitution degree, alkene content, and Irgacure 2959 loading. The proposed chemistry is plausible, but claims concerning product identity, reproducibility, six-month stability, and nanoparticle self-assembly require confirmation by quantitative NMR, two-dimensional NMR, size-exclusion chromatography, control reactions, dynamic light scattering, and complementary structural methods.