Drug delivery systems using chitosan nanoparticles
In the recent years considerable research efforts have been directed towards developing safe and efficient chitosan-based particulate drug delivery systems. Chitosan nanoparticles are good drug carriers because of their good biocompatibility and biodegradability, and can be readily modified. The primary hydroxyl and amine groups located on the backbone of chitosan allow for chemical modification to control its physical properties. When the hydrophobic moiety is conjugated to a chitosan molecule, the resulting amphiphile may form self-assembled nanoparticles that can encapsulate a quantity of drugs and deliver them to a specific site of action. Chemical attachment of the drug to the chitosan throughout the functional linker may produce useful prodrugs, exhibiting the appropriate biological activity at the target site. Mucoadhesion and absorption enhancement properties of chitosan increase the in vivo residence time in the gastrointestinal tract and improve the bioavailability of various insoluble drugs. The present review outlines the major new findings on the pharmaceutical applications of chitosan-based nanoparticulate drug delivery systems. The first part of the review is concerned with the organ-specific delivery system using chitosan and its derivatives. The subsequent section covers methods of their preparation, drug loading, release characteristics, and applications. Chemically modified chitosan have increased attention for their wide applications and their research discussed critically to evaluate usefulness of these systems in delivering the bioactive molecules. From literature survey, it is realized that research activities on chitosan nanoparticulate systems containing various drugs for different therapeutic applications have increased at the rapid rate. Hence, the present review is timely. Key Words: Chitosan, nanoparticles