Self-assembly of Novel Poly(d,l-Lactide-co-Glycolide)-b-Poly(N-Vinylpyrrolidone) (PLGA-b-PNVP) Amphiphilic Diblock Copolymers

Alkyne-terminated poly(d,l-lactide-co-glycolide) (PLGA) has been synthesized via ROP at room temperature. Amphiphilic PLGA-b-poly(N-vinylpyrrolidone) (PNVP) block copolymers have been synthesized via alkyne-azide click reaction of it with azide-terminated PNVPs prepared by RAFT polymerization of NVP using an azide-terminated RAFT agent. 1H NMR and gel permeation chromatography (GPC) confirmed the formation of block copolymers. Self-assembly of these block copolymers was confirmed by fluorescence study using pyrene as a probe and supported by 1H NMR, DLS and TEM studies. Hydrophobic drug doxorubicin was successfully encapsulated at the micellar core of PLGA46-b-PNVP89 with drug-loading content (DLC) and drug-loading efficiency (DLE) of 10.8 and 43.2 %, respectively. Sustained drug release of these drug-loaded micelles was observed at both pH of 6.4 and 7.4. Faster drug release was observed at pH 6.4. Such PLGA-b-PNVP amphiphilic block copolymer may find extensive application in sustained drug delivery, specifically in antitumor drug delivery.