ABSTRACT
Acknowledgments ..........................................................................................................................658 References ......................................................................................................................................658
Polymer nanoparticles are particles of less than 1 µm diameter that are prepared from natural or synthetic polymers. Nanoparticles have become an important area of research in the field of drug delivery because they have the ability to deliver a wide range of drugs to different areas of the body for sustained periods of time. The small size of nanoparticles is integral for systemic circulation. Natural polymers (i.e., proteins or polysaccharides) have not been widely used for this purpose since they vary in purity, and often require crosslinking that could denature the embedded drug. Consequently, synthetic polymers have received significantly more attention in this area. The most widely used polymers for nanoparticles have been poly-ε-caprolactone (PCL), poly(lactic acid) (PLA), poly(glycolic acid) (PGA), and their co-polymers, poly(lactide-co-glycolide) (PLGA) [1-3]. In addition, block co-polymers of PLA and poly(ethylene glycol) (PEG) and poly(amino acids) have been used to make nanoparticles and micelle-like structures [4,5]. These polymers are known for both their biocompatibility and resorbability through natural pathways. Additionally, the degradation rate and accordingly the drug release rate can be manipulated by varying the ratio of PLA or PCL, increased hydrophobicity, to PGA, and increased hydrophilicity.
