Chitosan and its Use as a Polymeric Drug Carrier Material in Dosage Form Design- A Critical Review

The prime goal in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. To minimize drug degradation/loss, prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are presently under investigation. Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. Microspheres are the choice of drug delivery system for the controlled release of drugs, vaccines, antibiotics, and hormones for specific target sites. There are various methods that can be used to encapsulate drugs within chitosan matrixes such as ionotropic gelation, spray drying, emulsification-solvent evaporation, co-acervation, double layer coating and many more. Combinations of these practices are also used in order to obtain micro-particles with specific properties and performances. Double-layer coating method is used to prevent the loss of encapsulated materials in the acidic medium. The microspheres should be coated with another polymer that forms a membrane on the surface. Due to the bilayer properties, the micro carriers additionally protected against acidic conditions of the stomach and drug releases in the intestine in a better controlled manner. This review focused on the techniques applied directly to chitosan micro-particulate systems and their role in novel drug delivery systems