Controlled drug delivery technology represents one of the most rapidly advancing areas of science in which chemists and chemical engineers are contributing to human health care. Such delivery systems offer numerous advantages compared to conventional dosage forms including improved efficacy, reduced toxicity, and improved patient compliance and convenience. Optimum therapeutic outcomes require not only proper drug selection but also effective drug delivery. Drugs can be delivered across the skin to have an effect on the tissues adjacent to the site of application (topical delivery) or to have...