drug delivery system chemistry 6 polymer 6 Drug Delivery Systems 5 Humans 5 Polymers 5 Drug Carriers 4 drug carrier 4 drug release 4 human 4 Article 3 Drug Liberation 3 controlled study 3 nanoparticle 3 particle size 3 Animals 2 Drug Compounding 2 Hydrogen-Ion Concentration 2 Hydrophobic and Hydrophilic Interactions 2 Ions 2 Micelles 2 Nanoparticles 2 Polyethylene Glycols 2 Povidone 2 Sustained-release 2 X ray diffraction 2 antineoplastic agent 2 camptothecin 2 chemical phenomena 2 crystallization 2