Novel self-assembly graft copolymers as carriers for anti-inflammatory drug delivery

Indomethacin (IMC) and quercetin (QUE) as typical models of anti-inflammatory drugs were loaded into the micelles of new amphiphilic graft copolymers, comprising caprolactone 2-(methacryloyloxy)ethyl ester (CLMA) units in the main chain and poly(meth)acrylic acid side chains (PAA/PMAA), which were studied as the carriers of drugs. The macromolecules were self-assembled by solvent evaporation or dialysis. The critical micelle concentration (CMC) ranged from 0.015 to 0.199 mg/ml. The copolymer composition, grafting degree and length of side chains, nature and content of hydrophobic/hydrophilic part, were investigated as the main parameters responsible for the properties of nanoparticles including their stability, core-drug interactions, improved drug solubility, and in consequence the efficiency of drug-loading and drug release profiles. The hydrodynamic diameters of particles measured by dynamic light scattering (DLS) ranged from 50 to 275 nm, and increased after loading with drug. In vitro release experiments performed at various pH (5.0 and 7.4) indicated faster release behavior from nanoparticles in acidic conditions (55-95% vs. 25-45% within 75 h).