PLGA-g-PVP amphiphilic bioactive and biocompatible copolymers for the fabrication of nanostructured materials

The aim of this work is to present a one-pot synthetic process leading to poly(lactide-co-glycolide)-g-poly(vinylpyrrolidone) (PLGA-g-PVP) copolymers consisting of high molecular weight PLGA carrying oligomeric PVP side chains. The title copolymers were prepared by chain transfer radical polymerization of N-vinylpyrrolidone in the presence of 50:50 PLGA, acting as polymeric chain transfer agent in the absence of solvents. All copolymers were characterized by 1H-NMR (400 MHz), FT-IR, SEC, MALDI-TOF, DSC, TGA and DLS techniques. PLGA is a lipophilic biodegradable polymer, whereas PVP is hydrophilic, biocompatible and also bioeliminable for molecular weights < 40.000. Both polymers have been approved for human use by the U.S. Food and Drug Administration, therefore the PLGA-g-PVP copolymers are eligible for medical applications. The water-soluble PVP portion imparts amphiphilicity to the otherwise hydrophobic PLGA, thus modifying its behavior in aqueous systems. In particular, PLGA-g-PVP samples spontaneously form nanoparticles when dispersed in water. These nanoparticles, besides dissolving hydrophobic drugs, for instance antimalarial drugs, in the inner core, are expected to show higher compatibility than native PLGA towards many drugs known to interact with PVP. In addition, PLGA-g-PVP samples, when used as additives, dramatically improved wettability of hydrophobic materials, as for instance polyesters, processed as nanofibers and intended for applications involving contact with the body fluids