Versatile UCST-based thermoresponsive hydrogels for loco- regional sustained drug delivery.
Versatile UCST-based thermoresponsive hydrogels for loco- regional sustained drug delivery.
Control. Release 174, 1–6 (2014).
Boustta, M., Colombo, P.-E., Lenglet, S., Poujol, S. & Vert, M.
ABSTRACT
Modification of the biodegradable and renewable poly(lactide) (PLA) to provide functional aliphatic polyesters is highly desirable to meet applications requirements. In this context, the objective of this work was to evaluate the possibility to use free-radical substitution as a simple and non-degrading method to yield the desired functional PLA. Halogenation of PLA was carried out in solution and various conditions of reaction have been evaluated. Halogenated PLAs were characterized by 1H NMR spectroscopy and size exclusion chromatography (SEC) to evaluate the substitution ratios and to check the non-degrading character of the radical modification. Furthermore, reactions on model compounds as well as MALDI-TOF analyses have been performed to elucidate the involved mechanism. The combined results proved the free-radical halogenation of PLA in solution to be regioselective with only the w-halogenated PLA being obtained without main-chain substitution.