During the past 30 years, extensive research has been pursued with modifiedand controlled-release drug delivery systems. The advantages of such systems

over traditional dosage forms include improved patient compliance and more

constant blood levels of drug, which can significantly increase the efficacy and reduce the side effects of the drug substance [1]. Recent advances in the field of drug delivery have resulted in the precise control of the level and location of

drug in the body. In addition, lower doses of medication to the patient are

needed [2].