ABSTRACT
This chapter highlights the major factors related to the use of nanoparticles fabricated from synthetic or natural polymeric materials that have been used in drug delivery and imaging. Polymers used in controlled drug delivery, including nanoparticles, may be classified as either natural and synthetic, or biodegradable and nonbiodegradable. Nonbiodegradable polymeric nanoparticles may be used for controlled drug delivery and also in the complimentary field of diagnostic imaging. Alginate nanoparticles are prepared by extruding an aqueous sodium alginate solution through a narrow-bore needle into an aqueous solution of a cationic agent, such as calcium ions, chitosan, or poly-l-lysine. The solubility spectrum of a polymer influences the method of preparation and in vivo performance of the nanoparticles. The particle size and particle size distribution are critical factors in the performance of nanoparticles, as batches with wide particle size distribution show significant variations in drug loading, drug release, bioavailability, and efficacy.
